Replaced several CopyOnWriteArrayList occurrences with ConcurrentHashMap.newKeySet().

L2J_Mobius_1.0_Ertheia/dist/game/data/scripts/ai/areas/FantasyIsle/Parade.java

@@ -17,7 +17,8 @@
 package ai.areas.FantasyIsle;
 
 import java.text.SimpleDateFormat;
-import java.util.concurrent.CopyOnWriteArrayList;
+import java.util.Collection;
+import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.ScheduledFuture;
 
 import org.l2jmobius.commons.concurrent.ThreadPool;
@@ -120,7 +121,7 @@ public class Parade extends AbstractNpcAI
 	// @formatter:on
 	
 	int npcIndex;
-	CopyOnWriteArrayList<Npc> spawns = new CopyOnWriteArrayList<>();
+	Collection<Npc> spawns = ConcurrentHashMap.newKeySet();
 	ScheduledFuture<?> spawnTask;
 	ScheduledFuture<?> deleteTask;
 	ScheduledFuture<?> cleanTask;

L2J_Mobius_1.0_Ertheia/dist/game/data/scripts/ai/bosses/Core/Core.java

@@ -16,11 +16,11 @@
  */
 package ai.bosses.Core;
 
+import java.util.Collection;
 import java.util.HashMap;
-import java.util.List;
 import java.util.Map;
 import java.util.Map.Entry;
-import java.util.concurrent.CopyOnWriteArrayList;
+import java.util.concurrent.ConcurrentHashMap;
 
 import org.l2jmobius.Config;
 import org.l2jmobius.gameserver.enums.ChatType;
@@ -78,7 +78,7 @@ public class Core extends AbstractNpcAI
 	
 	private static boolean _firstAttacked;
 	
-	private static final List<Attackable> _minions = new CopyOnWriteArrayList<>();
+	private static final Collection<Attackable> _minions = ConcurrentHashMap.newKeySet();
 	
 	private Core()
 	{

L2J_Mobius_1.0_Ertheia/dist/game/data/scripts/ai/others/SiegeGuards.java

@@ -16,8 +16,8 @@
  */
 package ai.others;
 
-import java.util.List;
+import java.util.Collection;
-import java.util.concurrent.CopyOnWriteArrayList;
+import java.util.concurrent.ConcurrentHashMap;
 
 import org.l2jmobius.gameserver.ai.CtrlIntention;
 import org.l2jmobius.gameserver.geoengine.GeoEngine;
@@ -87,7 +87,7 @@ public class SiegeGuards extends AbstractNpcAI
 		35134, 35135, 35136, 35176, 35177, 35178, 35218, 35219, 35220, 35261, 35262, 35263, 35264, 35265, 35308, 35309, 35310, 35352, 35353, 35354, 35497, 35498, 35499, 35500, 35501, 35544, 35545, 35546
 	};
 	//@formatter:on
-	private static final List<Npc> SPAWNED_GUARDS = new CopyOnWriteArrayList<>();
+	private static final Collection<Npc> SPAWNED_GUARDS = ConcurrentHashMap.newKeySet();
 	
 	public SiegeGuards()
 	{

L2J_Mobius_1.0_Ertheia/dist/game/data/scripts/custom/events/Rabbits/Rabbits.java

@@ -17,8 +17,9 @@
 package custom.events.Rabbits;
 
 import java.util.ArrayList;
+import java.util.Collection;
 import java.util.List;
-import java.util.concurrent.CopyOnWriteArrayList;
+import java.util.concurrent.ConcurrentHashMap;
 
 import org.l2jmobius.Config;
 import org.l2jmobius.commons.util.CommonUtil;
@@ -49,7 +50,7 @@ public class Rabbits extends Event
 	private static final int EVENT_TIME = 10;
 	private static final int TOTAL_CHEST_COUNT = 75;
 	private static final int TRANSFORMATION_ID = 105;
-	private final List<Npc> _npcs = new CopyOnWriteArrayList<>();
+	private final Collection<Npc> _npcs = ConcurrentHashMap.newKeySet();
 	private final List<PlayerInstance> _players = new ArrayList<>();
 	private boolean _isActive = false;
 	
@@ -253,7 +254,7 @@ public class Rabbits extends Event
 		}
 	}
 	
-	private void recordSpawn(List<Npc> npcs, int npcId, int x, int y, int z, int heading, boolean randomOffSet, long despawnDelay)
+	private void recordSpawn(Collection<Npc> npcs, int npcId, int x, int y, int z, int heading, boolean randomOffSet, long despawnDelay)
 	{
 		final Npc npc = addSpawn(npcId, x, y, z, heading, randomOffSet, despawnDelay);
 		if (npc.getId() == CHEST)

L2J_Mobius_1.0_Ertheia/dist/game/data/scripts/custom/events/Race/Race.java

@@ -17,8 +17,9 @@
 package custom.events.Race;
 
 import java.util.ArrayList;
+import java.util.Collection;
 import java.util.List;
-import java.util.concurrent.CopyOnWriteArrayList;
+import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.ScheduledFuture;
 
 import org.l2jmobius.Config;
@@ -45,7 +46,7 @@ public class Race extends Event
 	// Npc
 	private Npc _npc;
 	// Player list
-	private List<PlayerInstance> _players;
+	private Collection<PlayerInstance> _players;
 	// Event Task
 	ScheduledFuture<?> _eventTask = null;
 	// Event state
@@ -127,7 +128,7 @@ public class Race extends Event
 		}
 		// Initialize list
 		_npclist = new ArrayList<>();
-		_players = new CopyOnWriteArrayList<>();
+		_players = ConcurrentHashMap.newKeySet();
 		// Set Event active
 		_isactive = true;
 		// Spawn Manager

L2J_Mobius_1.0_Ertheia/java/org/l2jmobius/commons/util/IXmlReader.java

@@ -19,11 +19,12 @@ package org.l2jmobius.commons.util;
 import java.io.File;
 import java.io.FileFilter;
 import java.util.ArrayList;
+import java.util.Collection;
 import java.util.HashMap;
 import java.util.LinkedHashMap;
 import java.util.List;
 import java.util.Map;
-import java.util.concurrent.CopyOnWriteArrayList;
+import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.ScheduledFuture;
 import java.util.function.Consumer;
 import java.util.function.Predicate;
@@ -167,7 +168,7 @@ public interface IXmlReader
 		
 		if (Config.THREADS_FOR_LOADING)
 		{
-			final List<ScheduledFuture<?>> jobs = new CopyOnWriteArrayList<>();
+			final Collection<ScheduledFuture<?>> jobs = ConcurrentHashMap.newKeySet();
 			final File[] listOfFiles = dir.listFiles();
 			for (File file : listOfFiles)
 			{

L2J_Mobius_1.0_Ertheia/java/org/l2jmobius/gameserver/communitybbs/BB/Forum.java

@@ -19,10 +19,9 @@ package org.l2jmobius.gameserver.communitybbs.BB;
 import java.sql.Connection;
 import java.sql.PreparedStatement;
 import java.sql.ResultSet;
-import java.util.List;
+import java.util.Collection;
 import java.util.Map;
 import java.util.concurrent.ConcurrentHashMap;
-import java.util.concurrent.CopyOnWriteArrayList;
 import java.util.logging.Level;
 import java.util.logging.Logger;
 
@@ -46,7 +45,7 @@ public class Forum
 	public static final int CLANMEMBERONLY = 2;
 	public static final int OWNERONLY = 3;
 	
-	private final List<Forum> _children;
+	private final Collection<Forum> _children;
 	private final Map<Integer, Topic> _topic = new ConcurrentHashMap<>();
 	private final int _forumId;
 	private String _forumName;
@@ -66,7 +65,7 @@ public class Forum
 	{
 		_forumId = Forumid;
 		_fParent = FParent;
-		_children = new CopyOnWriteArrayList<>();
+		_children = ConcurrentHashMap.newKeySet();
 	}
 	
 	/**
@@ -85,7 +84,7 @@ public class Forum
 		_forumPerm = perm;
 		_fParent = parent;
 		_ownerID = OwnerID;
-		_children = new CopyOnWriteArrayList<>();
+		_children = ConcurrentHashMap.newKeySet();
 		parent._children.add(this);
 		ForumsBBSManager.getInstance().addForum(this);
 		_loaded = true;

L2J_Mobius_1.0_Ertheia/java/org/l2jmobius/gameserver/communitybbs/BB/Post.java

@@ -19,8 +19,8 @@ package org.l2jmobius.gameserver.communitybbs.BB;
 import java.sql.Connection;
 import java.sql.PreparedStatement;
 import java.sql.ResultSet;
-import java.util.List;
+import java.util.Collection;
-import java.util.concurrent.CopyOnWriteArrayList;
+import java.util.concurrent.ConcurrentHashMap;
 import java.util.logging.Level;
 import java.util.logging.Logger;
 
@@ -45,7 +45,7 @@ public class Post
 		public String postTxt;
 	}
 	
-	private final List<CPost> _post;
+	private final Collection<CPost> _post;
 	
 	/**
 	 * @param _PostOwner
@@ -57,7 +57,7 @@ public class Post
 	 */
 	public Post(String _PostOwner, int _PostOwnerID, long date, int tid, int _PostForumID, String txt)
 	{
-		_post = new CopyOnWriteArrayList<>();
+		_post = ConcurrentHashMap.newKeySet();
 		final CPost cp = new CPost();
 		cp.postId = 0;
 		cp.postOwner = _PostOwner;
@@ -92,7 +92,7 @@ public class Post
 	
 	public Post(Topic t)
 	{
-		_post = new CopyOnWriteArrayList<>();
+		_post = ConcurrentHashMap.newKeySet();
 		load(t);
 	}
 	

L2J_Mobius_1.0_Ertheia/java/org/l2jmobius/gameserver/communitybbs/Manager/ForumsBBSManager.java

@@ -19,8 +19,8 @@ package org.l2jmobius.gameserver.communitybbs.Manager;
 import java.sql.Connection;
 import java.sql.ResultSet;
 import java.sql.Statement;
-import java.util.List;
+import java.util.Collection;
-import java.util.concurrent.CopyOnWriteArrayList;
+import java.util.concurrent.ConcurrentHashMap;
 import java.util.logging.Level;
 import java.util.logging.Logger;
 
@@ -31,7 +31,7 @@ import org.l2jmobius.gameserver.model.actor.instance.PlayerInstance;
 public class ForumsBBSManager extends BaseBBSManager
 {
 	private static Logger LOGGER = Logger.getLogger(ForumsBBSManager.class.getName());
-	private final List<Forum> _table;
+	private final Collection<Forum> _table;
 	private int _lastid = 1;
 	
 	/**
@@ -39,7 +39,7 @@ public class ForumsBBSManager extends BaseBBSManager
 	 */
 	protected ForumsBBSManager()
 	{
-		_table = new CopyOnWriteArrayList<>();
+		_table = ConcurrentHashMap.newKeySet();
 		try (Connection con = DatabaseFactory.getConnection();
 			Statement s = con.createStatement();
 			ResultSet rs = s.executeQuery("SELECT forum_id FROM forums WHERE forum_type = 0"))

L2J_Mobius_1.0_Ertheia/java/org/l2jmobius/gameserver/communitybbs/Manager/TopicBBSManager.java

@@ -18,12 +18,11 @@ package org.l2jmobius.gameserver.communitybbs.Manager;
 
 import java.text.DateFormat;
 import java.util.Calendar;
+import java.util.Collection;
 import java.util.Date;
-import java.util.List;
 import java.util.Map;
 import java.util.StringTokenizer;
 import java.util.concurrent.ConcurrentHashMap;
-import java.util.concurrent.CopyOnWriteArrayList;
 
 import org.l2jmobius.gameserver.communitybbs.BB.Forum;
 import org.l2jmobius.gameserver.communitybbs.BB.Post;
@@ -34,7 +33,7 @@ import org.l2jmobius.gameserver.model.actor.instance.PlayerInstance;
 
 public class TopicBBSManager extends BaseBBSManager
 {
-	private final List<Topic> _table = new CopyOnWriteArrayList<>();
+	private final Collection<Topic> _table = ConcurrentHashMap.newKeySet();
 	private final Map<Forum, Integer> _maxId = new ConcurrentHashMap<>();
 	
 	protected TopicBBSManager()

L2J_Mobius_1.0_Ertheia/java/org/l2jmobius/gameserver/data/xml/impl/NpcData.java

@@ -18,6 +18,7 @@ package org.l2jmobius.gameserver.data.xml.impl;
 
 import java.io.File;
 import java.util.ArrayList;
+import java.util.Collection;
 import java.util.Collections;
 import java.util.EnumMap;
 import java.util.HashMap;
@@ -27,7 +28,6 @@ import java.util.Map;
 import java.util.Map.Entry;
 import java.util.Set;
 import java.util.concurrent.ConcurrentHashMap;
-import java.util.concurrent.CopyOnWriteArrayList;
 import java.util.function.Predicate;
 import java.util.logging.Logger;
 import java.util.stream.Collectors;
@@ -60,7 +60,7 @@ public class NpcData implements IXmlReader
 	
 	private final Map<Integer, NpcTemplate> _npcs = new ConcurrentHashMap<>();
 	private final Map<String, Integer> _clans = new ConcurrentHashMap<>();
-	private static final List<Integer> _masterMonsterIDs = new CopyOnWriteArrayList<>();
+	private static final Collection<Integer> _masterMonsterIDs = ConcurrentHashMap.newKeySet();
 	
 	protected NpcData()
 	{
@@ -789,7 +789,7 @@ public class NpcData implements IXmlReader
 	/**
 	 * @return the IDs of monsters that have minions.
 	 */
-	public static List<Integer> getMasterMonsterIDs()
+	public static Collection<Integer> getMasterMonsterIDs()
 	{
 		return _masterMonsterIDs;
 	}

L2J_Mobius_1.0_Ertheia/java/org/l2jmobius/gameserver/data/xml/impl/SpawnsData.java

@@ -18,10 +18,11 @@ package org.l2jmobius.gameserver.data.xml.impl;
 
 import java.io.File;
 import java.util.ArrayList;
+import java.util.Collection;
 import java.util.Collections;
 import java.util.List;
 import java.util.Map;
-import java.util.concurrent.CopyOnWriteArrayList;
+import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.ScheduledFuture;
 import java.util.function.Predicate;
 import java.util.logging.Level;
@@ -54,7 +55,7 @@ public class SpawnsData implements IXmlReader
 {
 	protected static final Logger LOGGER = Logger.getLogger(SpawnsData.class.getName());
 	
-	private final List<SpawnTemplate> _spawns = new CopyOnWriteArrayList<>();
+	private final Collection<SpawnTemplate> _spawns = ConcurrentHashMap.newKeySet();
 	
 	protected SpawnsData()
 	{
@@ -98,7 +99,7 @@ public class SpawnsData implements IXmlReader
 		
 		if (Config.THREADS_FOR_LOADING)
 		{
-			final List<ScheduledFuture<?>> jobs = new CopyOnWriteArrayList<>();
+			final Collection<ScheduledFuture<?>> jobs = ConcurrentHashMap.newKeySet();
 			for (SpawnTemplate template : _spawns)
 			{
 				if (template.isSpawningByDefault())
@@ -146,7 +147,7 @@ public class SpawnsData implements IXmlReader
 		LOGGER.info(getClass().getSimpleName() + ": All spawns has been removed!");
 	}
 	
-	public List<SpawnTemplate> getSpawns()
+	public Collection<SpawnTemplate> getSpawns()
 	{
 		return _spawns;
 	}
@@ -166,7 +167,7 @@ public class SpawnsData implements IXmlReader
 		return _spawns.stream().flatMap(template -> template.getGroups().stream()).flatMap(group -> group.getSpawns().stream()).filter(condition).collect(Collectors.toList());
 	}
 	
-	public void parseSpawn(Node spawnsNode, File file, List<SpawnTemplate> spawns)
+	public void parseSpawn(Node spawnsNode, File file, Collection<SpawnTemplate> spawns)
 	{
 		final SpawnTemplate spawnTemplate = new SpawnTemplate(new StatsSet(parseAttributes(spawnsNode)), file);
 		SpawnGroup defaultGroup = null;

L2J_Mobius_1.0_Ertheia/java/org/l2jmobius/gameserver/datatables/EventDroplist.java

@@ -16,10 +16,11 @@
  */
 package org.l2jmobius.gameserver.datatables;
 
+import java.util.Collection;
 import java.util.Date;
 import java.util.LinkedList;
 import java.util.List;
-import java.util.concurrent.CopyOnWriteArrayList;
+import java.util.concurrent.ConcurrentHashMap;
 
 import org.l2jmobius.gameserver.script.DateRange;
 import org.l2jmobius.gameserver.script.EventDrop;
@@ -35,7 +36,7 @@ public class EventDroplist
 	/**
 	 * The table containing all DataDrop object
 	 */
-	private static final List<DateDrop> ALL_NPC_DATE_DROPS = new CopyOnWriteArrayList<>();
+	private static final Collection<DateDrop> ALL_NPC_DATE_DROPS = ConcurrentHashMap.newKeySet();
 	
 	public static class DateDrop
 	{

L2J_Mobius_1.0_Ertheia/java/org/l2jmobius/gameserver/engines/DocumentEngine.java

@@ -18,8 +18,9 @@ package org.l2jmobius.gameserver.engines;
 
 import java.io.File;
 import java.util.ArrayList;
+import java.util.Collection;
 import java.util.List;
-import java.util.concurrent.CopyOnWriteArrayList;
+import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.ScheduledFuture;
 import java.util.logging.Logger;
 
@@ -66,13 +67,13 @@ public class DocumentEngine
 	 * Return created items
 	 * @return List of {@link Item}
 	 */
-	public List<Item> loadItems()
+	public Collection<Item> loadItems()
 	{
-		final List<Item> list = new CopyOnWriteArrayList<>();
+		final Collection<Item> list = ConcurrentHashMap.newKeySet();
 		
 		if (Config.THREADS_FOR_LOADING)
 		{
-			final List<ScheduledFuture<?>> jobs = new CopyOnWriteArrayList<>();
+			final Collection<ScheduledFuture<?>> jobs = ConcurrentHashMap.newKeySet();
 			for (File file : _itemFiles)
 			{
 				jobs.add(ThreadPool.schedule(() ->

L2J_Mobius_1.0_Ertheia/java/org/l2jmobius/gameserver/model/CommandChannel.java

@@ -16,9 +16,10 @@
  */
 package org.l2jmobius.gameserver.model;
 
+import java.util.Collection;
 import java.util.LinkedList;
 import java.util.List;
-import java.util.concurrent.CopyOnWriteArrayList;
+import java.util.concurrent.ConcurrentHashMap;
 import java.util.function.Function;
 
 import org.l2jmobius.Config;
@@ -36,7 +37,7 @@ import org.l2jmobius.gameserver.network.serverpackets.SystemMessage;
  */
 public class CommandChannel extends AbstractPlayerGroup
 {
-	private final List<Party> _parties = new CopyOnWriteArrayList<>();
+	private final Collection<Party> _parties = ConcurrentHashMap.newKeySet();
 	private PlayerInstance _commandLeader;
 	private int _channelLvl;
 	
@@ -150,7 +151,7 @@ public class CommandChannel extends AbstractPlayerGroup
 	/**
 	 * @return a list of all parties in this command channel
 	 */
-	public List<Party> getPartys()
+	public Collection<Party> getParties()
 	{
 		return _parties;
 	}

L2J_Mobius_1.0_Ertheia/java/org/l2jmobius/gameserver/model/Petition.java

@@ -16,8 +16,8 @@
  */
 package org.l2jmobius.gameserver.model;
 
-import java.util.List;
+import java.util.Collection;
-import java.util.concurrent.CopyOnWriteArrayList;
+import java.util.concurrent.ConcurrentHashMap;
 
 import org.l2jmobius.gameserver.enums.PetitionState;
 import org.l2jmobius.gameserver.enums.PetitionType;
@@ -41,7 +41,7 @@ public class Petition
 	private final PetitionType _type;
 	private PetitionState _state = PetitionState.PENDING;
 	private final String _content;
-	private final List<CreatureSay> _messageLog = new CopyOnWriteArrayList<>();
+	private final Collection<CreatureSay> _messageLog = ConcurrentHashMap.newKeySet();
 	private final PlayerInstance _petitioner;
 	private PlayerInstance _responder;
 	
@@ -58,7 +58,7 @@ public class Petition
 		return _messageLog.add(cs);
 	}
 	
-	public List<CreatureSay> getLogMessages()
+	public Collection<CreatureSay> getLogMessages()
 	{
 		return _messageLog;
 	}

L2J_Mobius_1.0_Ertheia/java/org/l2jmobius/gameserver/model/actor/instance/RaceManagerInstance.java

@@ -16,8 +16,8 @@
  */
 package org.l2jmobius.gameserver.model.actor.instance;
 
-import java.util.List;
+import java.util.Collection;
-import java.util.concurrent.CopyOnWriteArrayList;
+import java.util.concurrent.ConcurrentHashMap;
 
 import org.l2jmobius.Config;
 import org.l2jmobius.commons.concurrent.ThreadPool;
@@ -45,7 +45,7 @@ public class RaceManagerInstance extends Npc
 	public static final int LANES = 8;
 	public static final int WINDOW_START = 0;
 	
-	private static List<RaceManagerInstance> _managers;
+	private static Collection<RaceManagerInstance> _managers;
 	protected static int _raceNumber = 4;
 	
 	// Time Constants
@@ -104,7 +104,7 @@ public class RaceManagerInstance extends Npc
 		{
 			_notInitialized = false;
 			
-			_managers = new CopyOnWriteArrayList<>();
+			_managers = ConcurrentHashMap.newKeySet();
 			
 			ThreadPool.scheduleAtFixedRate(new Announcement(SystemMessageId.TICKETS_ARE_NOW_AVAILABLE_FOR_MONSTER_RACE_S1), 0, 10 * MINUTE);
 			ThreadPool.scheduleAtFixedRate(new Announcement(SystemMessageId.NOW_SELLING_TICKETS_FOR_MONSTER_RACE_S1), 30 * SECOND, 10 * MINUTE);

L2J_Mobius_1.0_Ertheia/java/org/l2jmobius/gameserver/model/actor/instance/ServitorInstance.java

@@ -19,10 +19,12 @@ package org.l2jmobius.gameserver.model.actor.instance;
 import java.sql.Connection;
 import java.sql.PreparedStatement;
 import java.sql.ResultSet;
+import java.util.Collection;
 import java.util.Collections;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.CopyOnWriteArrayList;
 import java.util.concurrent.Future;
 import java.util.logging.Level;
@@ -304,7 +306,7 @@ public class ServitorInstance extends Summon implements Runnable
 			
 			int buff_index = 0;
 			
-			final List<Long> storedSkills = new CopyOnWriteArrayList<>();
+			final Collection<Long> storedSkills = ConcurrentHashMap.newKeySet();
 			
 			// Store all effect data along with calculated remaining
 			if (storeEffects)

L2J_Mobius_1.0_Ertheia/java/org/l2jmobius/gameserver/model/actor/instance/TamedBeastInstance.java

@@ -18,8 +18,8 @@ package org.l2jmobius.gameserver.model.actor.instance;
 
 import static org.l2jmobius.gameserver.ai.CtrlIntention.AI_INTENTION_IDLE;
 
-import java.util.List;
+import java.util.Collection;
-import java.util.concurrent.CopyOnWriteArrayList;
+import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.Future;
 
 import org.l2jmobius.commons.concurrent.ThreadPool;
@@ -62,7 +62,7 @@ public class TamedBeastInstance extends FeedableBeastInstance
 	private Future<?> _buffTask = null;
 	private Future<?> _durationCheckTask = null;
 	protected boolean _isFreyaBeast;
-	private List<Skill> _beastSkills = null;
+	private Collection<Skill> _beastSkills = null;
 	
 	public TamedBeastInstance(int npcTemplateId)
 	{
@@ -205,7 +205,7 @@ public class TamedBeastInstance extends FeedableBeastInstance
 	{
 		if (_beastSkills == null)
 		{
-			_beastSkills = new CopyOnWriteArrayList<>();
+			_beastSkills = ConcurrentHashMap.newKeySet();
 		}
 		_beastSkills.add(skill);
 	}

L2J_Mobius_1.0_Ertheia/java/org/l2jmobius/gameserver/model/entity/Siegable.java

@@ -49,7 +49,7 @@ public interface Siegable
 	
 	SiegeClan getDefenderClan(Clan clan);
 	
-	List<SiegeClan> getDefenderClans();
+	Collection<SiegeClan> getDefenderClans();
 	
 	boolean checkIsDefender(Clan clan);
 	

L2J_Mobius_1.0_Ertheia/java/org/l2jmobius/gameserver/model/entity/Siege.java

@@ -21,12 +21,13 @@ import java.sql.PreparedStatement;
 import java.sql.ResultSet;
 import java.util.ArrayList;
 import java.util.Calendar;
+import java.util.Collection;
 import java.util.Collections;
 import java.util.Iterator;
 import java.util.List;
 import java.util.Objects;
 import java.util.Set;
-import java.util.concurrent.CopyOnWriteArrayList;
+import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.ScheduledFuture;
 import java.util.logging.Level;
 import java.util.logging.Logger;
@@ -221,9 +222,9 @@ public class Siege implements Siegable
 	}
 	
 	// must support Concurrent Modifications
-	private final List<SiegeClan> _attackerClans = new CopyOnWriteArrayList<>();
+	private final Collection<SiegeClan> _attackerClans = ConcurrentHashMap.newKeySet();
-	private final List<SiegeClan> _defenderClans = new CopyOnWriteArrayList<>();
+	private final Collection<SiegeClan> _defenderClans = ConcurrentHashMap.newKeySet();
-	private final List<SiegeClan> _defenderWaitingClans = new CopyOnWriteArrayList<>();
+	private final Collection<SiegeClan> _defenderWaitingClans = ConcurrentHashMap.newKeySet();
 	
 	// Castle setting
 	private final List<ControlTowerInstance> _controlTowers = new ArrayList<>();
@@ -1582,7 +1583,7 @@ public class Siege implements Siegable
 	}
 	
 	@Override
-	public List<SiegeClan> getAttackerClans()
+	public Collection<SiegeClan> getAttackerClans()
 	{
 		if (_isNormalSide)
 		{
@@ -1625,7 +1626,7 @@ public class Siege implements Siegable
 	}
 	
 	@Override
-	public List<SiegeClan> getDefenderClans()
+	public Collection<SiegeClan> getDefenderClans()
 	{
 		if (_isNormalSide)
 		{
@@ -1655,7 +1656,7 @@ public class Siege implements Siegable
 		return null;
 	}
 	
-	public List<SiegeClan> getDefenderWaitingClans()
+	public Collection<SiegeClan> getDefenderWaitingClans()
 	{
 		return _defenderWaitingClans;
 	}

L2J_Mobius_1.0_Ertheia/java/org/l2jmobius/gameserver/model/holders/MovieHolder.java

@@ -16,8 +16,9 @@
  */
 package org.l2jmobius.gameserver.model.holders;
 
+import java.util.Collection;
 import java.util.List;
-import java.util.concurrent.CopyOnWriteArrayList;
+import java.util.concurrent.ConcurrentHashMap;
 
 import org.l2jmobius.gameserver.enums.Movie;
 import org.l2jmobius.gameserver.model.actor.instance.PlayerInstance;
@@ -29,7 +30,7 @@ public class MovieHolder
 {
 	private final Movie _movie;
 	private final List<PlayerInstance> _players;
-	private final List<PlayerInstance> _votedPlayers = new CopyOnWriteArrayList<>();
+	private final Collection<PlayerInstance> _votedPlayers = ConcurrentHashMap.newKeySet();
 	
 	public MovieHolder(List<PlayerInstance> players, Movie movie)
 	{
@@ -64,7 +65,7 @@ public class MovieHolder
 		return _players;
 	}
 	
-	public List<PlayerInstance> getVotedPlayers()
+	public Collection<PlayerInstance> getVotedPlayers()
 	{
 		return _votedPlayers;
 	}

L2J_Mobius_1.0_Ertheia/java/org/l2jmobius/gameserver/model/matching/CommandChannelMatchingRoom.java

@@ -127,7 +127,7 @@ public class CommandChannelMatchingRoom extends MatchingRoom
 		if (leaderParty != null)
 		{
 			final CommandChannel cc = leaderParty.getCommandChannel();
-			if ((leaderParty == playerParty) || ((cc != null) && cc.getPartys().contains(playerParty)))
+			if ((leaderParty == playerParty) || ((cc != null) && cc.getParties().contains(playerParty)))
 			{
 				return MatchingMemberType.COMMAND_CHANNEL_PARTY_MEMBER;
 			}

L2J_Mobius_1.0_Ertheia/java/org/l2jmobius/gameserver/network/serverpackets/ExMultiPartyCommandChannelInfo.java

@@ -45,8 +45,8 @@ public class ExMultiPartyCommandChannelInfo implements IClientOutgoingPacket
 		packet.writeD(0x00); // Channel loot 0 or 1
 		packet.writeD(_channel.getMemberCount());
 		
-		packet.writeD(_channel.getPartys().size());
+		packet.writeD(_channel.getParties().size());
-		for (Party p : _channel.getPartys())
+		for (Party p : _channel.getParties())
 		{
 			packet.writeS(p.getLeader().getName());
 			packet.writeD(p.getLeaderObjectId());

L2J_Mobius_1.0_Ertheia/java/org/l2jmobius/gameserver/taskmanager/TaskManager.java

@@ -26,11 +26,10 @@ import java.sql.ResultSet;
 import java.sql.SQLException;
 import java.text.DateFormat;
 import java.util.Calendar;
+import java.util.Collection;
 import java.util.Date;
-import java.util.List;
 import java.util.Map;
 import java.util.concurrent.ConcurrentHashMap;
-import java.util.concurrent.CopyOnWriteArrayList;
 import java.util.concurrent.ScheduledFuture;
 import java.util.logging.Level;
 import java.util.logging.Logger;
@@ -50,7 +49,7 @@ public class TaskManager
 	static final Logger LOGGER = Logger.getLogger(TaskManager.class.getName());
 	
 	private final Map<Integer, Task> _tasks = new ConcurrentHashMap<>();
-	final List<ExecutedTask> _currentTasks = new CopyOnWriteArrayList<>();
+	final Collection<ExecutedTask> _currentTasks = ConcurrentHashMap.newKeySet();
 	
 	static final String[] SQL_STATEMENTS =
 	{

L2J_Mobius_1.0_Ertheia/java/org/l2jmobius/loginserver/GameServerListener.java

@@ -18,8 +18,8 @@ package org.l2jmobius.loginserver;
 
 import java.io.IOException;
 import java.net.Socket;
-import java.util.List;
+import java.util.Collection;
-import java.util.concurrent.CopyOnWriteArrayList;
+import java.util.concurrent.ConcurrentHashMap;
 
 import org.l2jmobius.Config;
 
@@ -28,7 +28,7 @@ import org.l2jmobius.Config;
  */
 public class GameServerListener extends FloodProtectedListener
 {
-	private static List<GameServerThread> _gameServers = new CopyOnWriteArrayList<>();
+	private static Collection<GameServerThread> _gameServers = ConcurrentHashMap.newKeySet();
 	
 	public GameServerListener() throws IOException
 	{

L2J_Mobius_2.5_Underground/dist/game/data/scripts/ai/areas/FantasyIsle/Parade.java

@@ -17,7 +17,8 @@
 package ai.areas.FantasyIsle;
 
 import java.text.SimpleDateFormat;
-import java.util.concurrent.CopyOnWriteArrayList;
+import java.util.Collection;
+import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.ScheduledFuture;
 
 import org.l2jmobius.commons.concurrent.ThreadPool;
@@ -120,7 +121,7 @@ public class Parade extends AbstractNpcAI
 	// @formatter:on
 	
 	int npcIndex;
-	CopyOnWriteArrayList<Npc> spawns = new CopyOnWriteArrayList<>();
+	Collection<Npc> spawns = ConcurrentHashMap.newKeySet();
 	ScheduledFuture<?> spawnTask;
 	ScheduledFuture<?> deleteTask;
 	ScheduledFuture<?> cleanTask;

L2J_Mobius_2.5_Underground/dist/game/data/scripts/ai/bosses/Core/Core.java

@@ -16,11 +16,11 @@
  */
 package ai.bosses.Core;
 
+import java.util.Collection;
 import java.util.HashMap;
-import java.util.List;
 import java.util.Map;
 import java.util.Map.Entry;
-import java.util.concurrent.CopyOnWriteArrayList;
+import java.util.concurrent.ConcurrentHashMap;
 
 import org.l2jmobius.Config;
 import org.l2jmobius.gameserver.enums.ChatType;
@@ -78,7 +78,7 @@ public class Core extends AbstractNpcAI
 	
 	private static boolean _firstAttacked;
 	
-	private static final List<Attackable> _minions = new CopyOnWriteArrayList<>();
+	private static final Collection<Attackable> _minions = ConcurrentHashMap.newKeySet();
 	
 	private Core()
 	{

L2J_Mobius_2.5_Underground/dist/game/data/scripts/ai/others/SiegeGuards.java

@@ -16,8 +16,8 @@
  */
 package ai.others;
 
-import java.util.List;
+import java.util.Collection;
-import java.util.concurrent.CopyOnWriteArrayList;
+import java.util.concurrent.ConcurrentHashMap;
 
 import org.l2jmobius.gameserver.ai.CtrlIntention;
 import org.l2jmobius.gameserver.geoengine.GeoEngine;
@@ -87,7 +87,7 @@ public class SiegeGuards extends AbstractNpcAI
 		35134, 35135, 35136, 35176, 35177, 35178, 35218, 35219, 35220, 35261, 35262, 35263, 35264, 35265, 35308, 35309, 35310, 35352, 35353, 35354, 35497, 35498, 35499, 35500, 35501, 35544, 35545, 35546
 	};
 	//@formatter:on
-	private static final List<Npc> SPAWNED_GUARDS = new CopyOnWriteArrayList<>();
+	private static final Collection<Npc> SPAWNED_GUARDS = ConcurrentHashMap.newKeySet();
 	
 	public SiegeGuards()
 	{

L2J_Mobius_2.5_Underground/dist/game/data/scripts/custom/events/Rabbits/Rabbits.java

@@ -17,8 +17,9 @@
 package custom.events.Rabbits;
 
 import java.util.ArrayList;
+import java.util.Collection;
 import java.util.List;
-import java.util.concurrent.CopyOnWriteArrayList;
+import java.util.concurrent.ConcurrentHashMap;
 
 import org.l2jmobius.Config;
 import org.l2jmobius.commons.util.CommonUtil;
@@ -49,7 +50,7 @@ public class Rabbits extends Event
 	private static final int EVENT_TIME = 10;
 	private static final int TOTAL_CHEST_COUNT = 75;
 	private static final int TRANSFORMATION_ID = 105;
-	private final List<Npc> _npcs = new CopyOnWriteArrayList<>();
+	private final Collection<Npc> _npcs = ConcurrentHashMap.newKeySet();
 	private final List<PlayerInstance> _players = new ArrayList<>();
 	private boolean _isActive = false;
 	
@@ -253,7 +254,7 @@ public class Rabbits extends Event
 		}
 	}
 	
-	private void recordSpawn(List<Npc> npcs, int npcId, int x, int y, int z, int heading, boolean randomOffSet, long despawnDelay)
+	private void recordSpawn(Collection<Npc> npcs, int npcId, int x, int y, int z, int heading, boolean randomOffSet, long despawnDelay)
 	{
 		final Npc npc = addSpawn(npcId, x, y, z, heading, randomOffSet, despawnDelay);
 		if (npc.getId() == CHEST)

L2J_Mobius_2.5_Underground/dist/game/data/scripts/custom/events/Race/Race.java

@@ -17,8 +17,9 @@
 package custom.events.Race;
 
 import java.util.ArrayList;
+import java.util.Collection;
 import java.util.List;
-import java.util.concurrent.CopyOnWriteArrayList;
+import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.ScheduledFuture;
 
 import org.l2jmobius.Config;
@@ -45,7 +46,7 @@ public class Race extends Event
 	// Npc
 	private Npc _npc;
 	// Player list
-	private List<PlayerInstance> _players;
+	private Collection<PlayerInstance> _players;
 	// Event Task
 	ScheduledFuture<?> _eventTask = null;
 	// Event state
@@ -127,7 +128,7 @@ public class Race extends Event
 		}
 		// Initialize list
 		_npclist = new ArrayList<>();
-		_players = new CopyOnWriteArrayList<>();
+		_players = ConcurrentHashMap.newKeySet();
 		// Set Event active
 		_isactive = true;
 		// Spawn Manager

L2J_Mobius_2.5_Underground/java/org/l2jmobius/commons/util/IXmlReader.java

@@ -19,11 +19,12 @@ package org.l2jmobius.commons.util;
 import java.io.File;
 import java.io.FileFilter;
 import java.util.ArrayList;
+import java.util.Collection;
 import java.util.HashMap;
 import java.util.LinkedHashMap;
 import java.util.List;
 import java.util.Map;
-import java.util.concurrent.CopyOnWriteArrayList;
+import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.ScheduledFuture;
 import java.util.function.Consumer;
 import java.util.function.Predicate;
@@ -167,7 +168,7 @@ public interface IXmlReader
 		
 		if (Config.THREADS_FOR_LOADING)
 		{
-			final List<ScheduledFuture<?>> jobs = new CopyOnWriteArrayList<>();
+			final Collection<ScheduledFuture<?>> jobs = ConcurrentHashMap.newKeySet();
 			final File[] listOfFiles = dir.listFiles();
 			for (File file : listOfFiles)
 			{

L2J_Mobius_2.5_Underground/java/org/l2jmobius/gameserver/communitybbs/BB/Forum.java

@@ -19,10 +19,9 @@ package org.l2jmobius.gameserver.communitybbs.BB;
 import java.sql.Connection;
 import java.sql.PreparedStatement;
 import java.sql.ResultSet;
-import java.util.List;
+import java.util.Collection;
 import java.util.Map;
 import java.util.concurrent.ConcurrentHashMap;
-import java.util.concurrent.CopyOnWriteArrayList;
 import java.util.logging.Level;
 import java.util.logging.Logger;
 
@@ -46,7 +45,7 @@ public class Forum
 	public static final int CLANMEMBERONLY = 2;
 	public static final int OWNERONLY = 3;
 	
-	private final List<Forum> _children;
+	private final Collection<Forum> _children;
 	private final Map<Integer, Topic> _topic = new ConcurrentHashMap<>();
 	private final int _forumId;
 	private String _forumName;
@@ -66,7 +65,7 @@ public class Forum
 	{
 		_forumId = Forumid;
 		_fParent = FParent;
-		_children = new CopyOnWriteArrayList<>();
+		_children = ConcurrentHashMap.newKeySet();
 	}
 	
 	/**
@@ -85,7 +84,7 @@ public class Forum
 		_forumPerm = perm;
 		_fParent = parent;
 		_ownerID = OwnerID;
-		_children = new CopyOnWriteArrayList<>();
+		_children = ConcurrentHashMap.newKeySet();
 		parent._children.add(this);
 		ForumsBBSManager.getInstance().addForum(this);
 		_loaded = true;

L2J_Mobius_2.5_Underground/java/org/l2jmobius/gameserver/communitybbs/BB/Post.java

@@ -19,8 +19,8 @@ package org.l2jmobius.gameserver.communitybbs.BB;
 import java.sql.Connection;
 import java.sql.PreparedStatement;
 import java.sql.ResultSet;
-import java.util.List;
+import java.util.Collection;
-import java.util.concurrent.CopyOnWriteArrayList;
+import java.util.concurrent.ConcurrentHashMap;
 import java.util.logging.Level;
 import java.util.logging.Logger;
 
@@ -45,7 +45,7 @@ public class Post
 		public String postTxt;
 	}
 	
-	private final List<CPost> _post;
+	private final Collection<CPost> _post;
 	
 	/**
 	 * @param _PostOwner
@@ -57,7 +57,7 @@ public class Post
 	 */
 	public Post(String _PostOwner, int _PostOwnerID, long date, int tid, int _PostForumID, String txt)
 	{
-		_post = new CopyOnWriteArrayList<>();
+		_post = ConcurrentHashMap.newKeySet();
 		final CPost cp = new CPost();
 		cp.postId = 0;
 		cp.postOwner = _PostOwner;
@@ -92,7 +92,7 @@ public class Post
 	
 	public Post(Topic t)
 	{
-		_post = new CopyOnWriteArrayList<>();
+		_post = ConcurrentHashMap.newKeySet();
 		load(t);
 	}
 	

L2J_Mobius_2.5_Underground/java/org/l2jmobius/gameserver/communitybbs/Manager/ForumsBBSManager.java

@@ -19,8 +19,8 @@ package org.l2jmobius.gameserver.communitybbs.Manager;
 import java.sql.Connection;
 import java.sql.ResultSet;
 import java.sql.Statement;
-import java.util.List;
+import java.util.Collection;
-import java.util.concurrent.CopyOnWriteArrayList;
+import java.util.concurrent.ConcurrentHashMap;
 import java.util.logging.Level;
 import java.util.logging.Logger;
 
@@ -31,7 +31,7 @@ import org.l2jmobius.gameserver.model.actor.instance.PlayerInstance;
 public class ForumsBBSManager extends BaseBBSManager
 {
 	private static Logger LOGGER = Logger.getLogger(ForumsBBSManager.class.getName());
-	private final List<Forum> _table;
+	private final Collection<Forum> _table;
 	private int _lastid = 1;
 	
 	/**
@@ -39,7 +39,7 @@ public class ForumsBBSManager extends BaseBBSManager
 	 */
 	protected ForumsBBSManager()
 	{
-		_table = new CopyOnWriteArrayList<>();
+		_table = ConcurrentHashMap.newKeySet();
 		try (Connection con = DatabaseFactory.getConnection();
 			Statement s = con.createStatement();
 			ResultSet rs = s.executeQuery("SELECT forum_id FROM forums WHERE forum_type = 0"))

L2J_Mobius_2.5_Underground/java/org/l2jmobius/gameserver/communitybbs/Manager/TopicBBSManager.java

@@ -18,12 +18,11 @@ package org.l2jmobius.gameserver.communitybbs.Manager;
 
 import java.text.DateFormat;
 import java.util.Calendar;
+import java.util.Collection;
 import java.util.Date;
-import java.util.List;
 import java.util.Map;
 import java.util.StringTokenizer;
 import java.util.concurrent.ConcurrentHashMap;
-import java.util.concurrent.CopyOnWriteArrayList;
 
 import org.l2jmobius.gameserver.communitybbs.BB.Forum;
 import org.l2jmobius.gameserver.communitybbs.BB.Post;
@@ -34,7 +33,7 @@ import org.l2jmobius.gameserver.model.actor.instance.PlayerInstance;
 
 public class TopicBBSManager extends BaseBBSManager
 {
-	private final List<Topic> _table = new CopyOnWriteArrayList<>();
+	private final Collection<Topic> _table = ConcurrentHashMap.newKeySet();
 	private final Map<Forum, Integer> _maxId = new ConcurrentHashMap<>();
 	
 	protected TopicBBSManager()

L2J_Mobius_2.5_Underground/java/org/l2jmobius/gameserver/data/xml/impl/NpcData.java

@@ -18,6 +18,7 @@ package org.l2jmobius.gameserver.data.xml.impl;
 
 import java.io.File;
 import java.util.ArrayList;
+import java.util.Collection;
 import java.util.Collections;
 import java.util.EnumMap;
 import java.util.HashMap;
@@ -27,7 +28,6 @@ import java.util.Map;
 import java.util.Map.Entry;
 import java.util.Set;
 import java.util.concurrent.ConcurrentHashMap;
-import java.util.concurrent.CopyOnWriteArrayList;
 import java.util.function.Predicate;
 import java.util.logging.Logger;
 import java.util.stream.Collectors;
@@ -60,7 +60,7 @@ public class NpcData implements IXmlReader
 	
 	private final Map<Integer, NpcTemplate> _npcs = new ConcurrentHashMap<>();
 	private final Map<String, Integer> _clans = new ConcurrentHashMap<>();
-	private static final List<Integer> _masterMonsterIDs = new CopyOnWriteArrayList<>();
+	private static final Collection<Integer> _masterMonsterIDs = ConcurrentHashMap.newKeySet();
 	
 	protected NpcData()
 	{
@@ -789,7 +789,7 @@ public class NpcData implements IXmlReader
 	/**
 	 * @return the IDs of monsters that have minions.
 	 */
-	public static List<Integer> getMasterMonsterIDs()
+	public static Collection<Integer> getMasterMonsterIDs()
 	{
 		return _masterMonsterIDs;
 	}

L2J_Mobius_2.5_Underground/java/org/l2jmobius/gameserver/data/xml/impl/SpawnsData.java

@@ -18,10 +18,11 @@ package org.l2jmobius.gameserver.data.xml.impl;
 
 import java.io.File;
 import java.util.ArrayList;
+import java.util.Collection;
 import java.util.Collections;
 import java.util.List;
 import java.util.Map;
-import java.util.concurrent.CopyOnWriteArrayList;
+import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.ScheduledFuture;
 import java.util.function.Predicate;
 import java.util.logging.Level;
@@ -54,7 +55,7 @@ public class SpawnsData implements IXmlReader
 {
 	protected static final Logger LOGGER = Logger.getLogger(SpawnsData.class.getName());
 	
-	private final List<SpawnTemplate> _spawns = new CopyOnWriteArrayList<>();
+	private final Collection<SpawnTemplate> _spawns = ConcurrentHashMap.newKeySet();
 	
 	protected SpawnsData()
 	{
@@ -98,7 +99,7 @@ public class SpawnsData implements IXmlReader
 		
 		if (Config.THREADS_FOR_LOADING)
 		{
-			final List<ScheduledFuture<?>> jobs = new CopyOnWriteArrayList<>();
+			final Collection<ScheduledFuture<?>> jobs = ConcurrentHashMap.newKeySet();
 			for (SpawnTemplate template : _spawns)
 			{
 				if (template.isSpawningByDefault())
@@ -146,7 +147,7 @@ public class SpawnsData implements IXmlReader
 		LOGGER.info(getClass().getSimpleName() + ": All spawns has been removed!");
 	}
 	
-	public List<SpawnTemplate> getSpawns()
+	public Collection<SpawnTemplate> getSpawns()
 	{
 		return _spawns;
 	}
@@ -166,7 +167,7 @@ public class SpawnsData implements IXmlReader
 		return _spawns.stream().flatMap(template -> template.getGroups().stream()).flatMap(group -> group.getSpawns().stream()).filter(condition).collect(Collectors.toList());
 	}
 	
-	public void parseSpawn(Node spawnsNode, File file, List<SpawnTemplate> spawns)
+	public void parseSpawn(Node spawnsNode, File file, Collection<SpawnTemplate> spawns)
 	{
 		final SpawnTemplate spawnTemplate = new SpawnTemplate(new StatsSet(parseAttributes(spawnsNode)), file);
 		SpawnGroup defaultGroup = null;

L2J_Mobius_2.5_Underground/java/org/l2jmobius/gameserver/datatables/EventDroplist.java

@@ -16,10 +16,11 @@
  */
 package org.l2jmobius.gameserver.datatables;
 
+import java.util.Collection;
 import java.util.Date;
 import java.util.LinkedList;
 import java.util.List;
-import java.util.concurrent.CopyOnWriteArrayList;
+import java.util.concurrent.ConcurrentHashMap;
 
 import org.l2jmobius.gameserver.script.DateRange;
 import org.l2jmobius.gameserver.script.EventDrop;
@@ -35,7 +36,7 @@ public class EventDroplist
 	/**
 	 * The table containing all DataDrop object
 	 */
-	private static final List<DateDrop> ALL_NPC_DATE_DROPS = new CopyOnWriteArrayList<>();
+	private static final Collection<DateDrop> ALL_NPC_DATE_DROPS = ConcurrentHashMap.newKeySet();
 	
 	public static class DateDrop
 	{

L2J_Mobius_2.5_Underground/java/org/l2jmobius/gameserver/engines/DocumentEngine.java

@@ -18,8 +18,9 @@ package org.l2jmobius.gameserver.engines;
 
 import java.io.File;
 import java.util.ArrayList;
+import java.util.Collection;
 import java.util.List;
-import java.util.concurrent.CopyOnWriteArrayList;
+import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.ScheduledFuture;
 import java.util.logging.Logger;
 
@@ -66,13 +67,13 @@ public class DocumentEngine
 	 * Return created items
 	 * @return List of {@link Item}
 	 */
-	public List<Item> loadItems()
+	public Collection<Item> loadItems()
 	{
-		final List<Item> list = new CopyOnWriteArrayList<>();
+		final Collection<Item> list = ConcurrentHashMap.newKeySet();
 		
 		if (Config.THREADS_FOR_LOADING)
 		{
-			final List<ScheduledFuture<?>> jobs = new CopyOnWriteArrayList<>();
+			final Collection<ScheduledFuture<?>> jobs = ConcurrentHashMap.newKeySet();
 			for (File file : _itemFiles)
 			{
 				jobs.add(ThreadPool.schedule(() ->

L2J_Mobius_2.5_Underground/java/org/l2jmobius/gameserver/model/CommandChannel.java

@@ -16,9 +16,10 @@
  */
 package org.l2jmobius.gameserver.model;
 
+import java.util.Collection;
 import java.util.LinkedList;
 import java.util.List;
-import java.util.concurrent.CopyOnWriteArrayList;
+import java.util.concurrent.ConcurrentHashMap;
 import java.util.function.Function;
 
 import org.l2jmobius.Config;
@@ -36,7 +37,7 @@ import org.l2jmobius.gameserver.network.serverpackets.SystemMessage;
  */
 public class CommandChannel extends AbstractPlayerGroup
 {
-	private final List<Party> _parties = new CopyOnWriteArrayList<>();
+	private final Collection<Party> _parties = ConcurrentHashMap.newKeySet();
 	private PlayerInstance _commandLeader;
 	private int _channelLvl;
 	
@@ -150,7 +151,7 @@ public class CommandChannel extends AbstractPlayerGroup
 	/**
 	 * @return a list of all parties in this command channel
 	 */
-	public List<Party> getPartys()
+	public Collection<Party> getParties()
 	{
 		return _parties;
 	}

L2J_Mobius_2.5_Underground/java/org/l2jmobius/gameserver/model/Petition.java

@@ -16,8 +16,8 @@
  */
 package org.l2jmobius.gameserver.model;
 
-import java.util.List;
+import java.util.Collection;
-import java.util.concurrent.CopyOnWriteArrayList;
+import java.util.concurrent.ConcurrentHashMap;
 
 import org.l2jmobius.gameserver.enums.PetitionState;
 import org.l2jmobius.gameserver.enums.PetitionType;
@@ -41,7 +41,7 @@ public class Petition
 	private final PetitionType _type;
 	private PetitionState _state = PetitionState.PENDING;
 	private final String _content;
-	private final List<CreatureSay> _messageLog = new CopyOnWriteArrayList<>();
+	private final Collection<CreatureSay> _messageLog = ConcurrentHashMap.newKeySet();
 	private final PlayerInstance _petitioner;
 	private PlayerInstance _responder;
 	
@@ -58,7 +58,7 @@ public class Petition
 		return _messageLog.add(cs);
 	}
 	
-	public List<CreatureSay> getLogMessages()
+	public Collection<CreatureSay> getLogMessages()
 	{
 		return _messageLog;
 	}

L2J_Mobius_2.5_Underground/java/org/l2jmobius/gameserver/model/actor/instance/RaceManagerInstance.java

@@ -16,8 +16,8 @@
  */
 package org.l2jmobius.gameserver.model.actor.instance;
 
-import java.util.List;
+import java.util.Collection;
-import java.util.concurrent.CopyOnWriteArrayList;
+import java.util.concurrent.ConcurrentHashMap;
 
 import org.l2jmobius.Config;
 import org.l2jmobius.commons.concurrent.ThreadPool;
@@ -45,7 +45,7 @@ public class RaceManagerInstance extends Npc
 	public static final int LANES = 8;
 	public static final int WINDOW_START = 0;
 	
-	private static List<RaceManagerInstance> _managers;
+	private static Collection<RaceManagerInstance> _managers;
 	protected static int _raceNumber = 4;
 	
 	// Time Constants
@@ -104,7 +104,7 @@ public class RaceManagerInstance extends Npc
 		{
 			_notInitialized = false;
 			
-			_managers = new CopyOnWriteArrayList<>();
+			_managers = ConcurrentHashMap.newKeySet();
 			
 			ThreadPool.scheduleAtFixedRate(new Announcement(SystemMessageId.TICKETS_ARE_NOW_AVAILABLE_FOR_MONSTER_RACE_S1), 0, 10 * MINUTE);
 			ThreadPool.scheduleAtFixedRate(new Announcement(SystemMessageId.NOW_SELLING_TICKETS_FOR_MONSTER_RACE_S1), 30 * SECOND, 10 * MINUTE);

L2J_Mobius_2.5_Underground/java/org/l2jmobius/gameserver/model/actor/instance/ServitorInstance.java

@@ -19,10 +19,12 @@ package org.l2jmobius.gameserver.model.actor.instance;
 import java.sql.Connection;
 import java.sql.PreparedStatement;
 import java.sql.ResultSet;
+import java.util.Collection;
 import java.util.Collections;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.CopyOnWriteArrayList;
 import java.util.concurrent.Future;
 import java.util.logging.Level;
@@ -304,7 +306,7 @@ public class ServitorInstance extends Summon implements Runnable
 			
 			int buff_index = 0;
 			
-			final List<Long> storedSkills = new CopyOnWriteArrayList<>();
+			final Collection<Long> storedSkills = ConcurrentHashMap.newKeySet();
 			
 			// Store all effect data along with calculated remaining
 			if (storeEffects)

L2J_Mobius_2.5_Underground/java/org/l2jmobius/gameserver/model/actor/instance/TamedBeastInstance.java

@@ -18,8 +18,8 @@ package org.l2jmobius.gameserver.model.actor.instance;
 
 import static org.l2jmobius.gameserver.ai.CtrlIntention.AI_INTENTION_IDLE;
 
-import java.util.List;
+import java.util.Collection;
-import java.util.concurrent.CopyOnWriteArrayList;
+import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.Future;
 
 import org.l2jmobius.commons.concurrent.ThreadPool;
@@ -62,7 +62,7 @@ public class TamedBeastInstance extends FeedableBeastInstance
 	private Future<?> _buffTask = null;
 	private Future<?> _durationCheckTask = null;
 	protected boolean _isFreyaBeast;
-	private List<Skill> _beastSkills = null;
+	private Collection<Skill> _beastSkills = null;
 	
 	public TamedBeastInstance(int npcTemplateId)
 	{
@@ -205,7 +205,7 @@ public class TamedBeastInstance extends FeedableBeastInstance
 	{
 		if (_beastSkills == null)
 		{
-			_beastSkills = new CopyOnWriteArrayList<>();
+			_beastSkills = ConcurrentHashMap.newKeySet();
 		}
 		_beastSkills.add(skill);
 	}

L2J_Mobius_2.5_Underground/java/org/l2jmobius/gameserver/model/entity/Siegable.java

@@ -49,7 +49,7 @@ public interface Siegable
 	
 	SiegeClan getDefenderClan(Clan clan);
 	
-	List<SiegeClan> getDefenderClans();
+	Collection<SiegeClan> getDefenderClans();
 	
 	boolean checkIsDefender(Clan clan);
 	

L2J_Mobius_2.5_Underground/java/org/l2jmobius/gameserver/model/entity/Siege.java

@@ -21,12 +21,13 @@ import java.sql.PreparedStatement;
 import java.sql.ResultSet;
 import java.util.ArrayList;
 import java.util.Calendar;
+import java.util.Collection;
 import java.util.Collections;
 import java.util.Iterator;
 import java.util.List;
 import java.util.Objects;
 import java.util.Set;
-import java.util.concurrent.CopyOnWriteArrayList;
+import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.ScheduledFuture;
 import java.util.logging.Level;
 import java.util.logging.Logger;
@@ -221,9 +222,9 @@ public class Siege implements Siegable
 	}
 	
 	// must support Concurrent Modifications
-	private final List<SiegeClan> _attackerClans = new CopyOnWriteArrayList<>();
+	private final Collection<SiegeClan> _attackerClans = ConcurrentHashMap.newKeySet();
-	private final List<SiegeClan> _defenderClans = new CopyOnWriteArrayList<>();
+	private final Collection<SiegeClan> _defenderClans = ConcurrentHashMap.newKeySet();
-	private final List<SiegeClan> _defenderWaitingClans = new CopyOnWriteArrayList<>();
+	private final Collection<SiegeClan> _defenderWaitingClans = ConcurrentHashMap.newKeySet();
 	
 	// Castle setting
 	private final List<ControlTowerInstance> _controlTowers = new ArrayList<>();
@@ -1582,7 +1583,7 @@ public class Siege implements Siegable
 	}
 	
 	@Override
-	public List<SiegeClan> getAttackerClans()
+	public Collection<SiegeClan> getAttackerClans()
 	{
 		if (_isNormalSide)
 		{
@@ -1625,7 +1626,7 @@ public class Siege implements Siegable
 	}
 	
 	@Override
-	public List<SiegeClan> getDefenderClans()
+	public Collection<SiegeClan> getDefenderClans()
 	{
 		if (_isNormalSide)
 		{
@@ -1655,7 +1656,7 @@ public class Siege implements Siegable
 		return null;
 	}
 	
-	public List<SiegeClan> getDefenderWaitingClans()
+	public Collection<SiegeClan> getDefenderWaitingClans()
 	{
 		return _defenderWaitingClans;
 	}

L2J_Mobius_2.5_Underground/java/org/l2jmobius/gameserver/model/holders/MovieHolder.java

@@ -16,8 +16,9 @@
  */
 package org.l2jmobius.gameserver.model.holders;
 
+import java.util.Collection;
 import java.util.List;
-import java.util.concurrent.CopyOnWriteArrayList;
+import java.util.concurrent.ConcurrentHashMap;
 
 import org.l2jmobius.gameserver.enums.Movie;
 import org.l2jmobius.gameserver.model.actor.instance.PlayerInstance;
@@ -29,7 +30,7 @@ public class MovieHolder
 {
 	private final Movie _movie;
 	private final List<PlayerInstance> _players;
-	private final List<PlayerInstance> _votedPlayers = new CopyOnWriteArrayList<>();
+	private final Collection<PlayerInstance> _votedPlayers = ConcurrentHashMap.newKeySet();
 	
 	public MovieHolder(List<PlayerInstance> players, Movie movie)
 	{
@@ -64,7 +65,7 @@ public class MovieHolder
 		return _players;
 	}
 	
-	public List<PlayerInstance> getVotedPlayers()
+	public Collection<PlayerInstance> getVotedPlayers()
 	{
 		return _votedPlayers;
 	}

L2J_Mobius_2.5_Underground/java/org/l2jmobius/gameserver/model/matching/CommandChannelMatchingRoom.java

@@ -127,7 +127,7 @@ public class CommandChannelMatchingRoom extends MatchingRoom
 		if (leaderParty != null)
 		{
 			final CommandChannel cc = leaderParty.getCommandChannel();
-			if ((leaderParty == playerParty) || ((cc != null) && cc.getPartys().contains(playerParty)))
+			if ((leaderParty == playerParty) || ((cc != null) && cc.getParties().contains(playerParty)))
 			{
 				return MatchingMemberType.COMMAND_CHANNEL_PARTY_MEMBER;
 			}

L2J_Mobius_2.5_Underground/java/org/l2jmobius/gameserver/network/serverpackets/ExMultiPartyCommandChannelInfo.java

@@ -45,8 +45,8 @@ public class ExMultiPartyCommandChannelInfo implements IClientOutgoingPacket
 		packet.writeD(0x00); // Channel loot 0 or 1
 		packet.writeD(_channel.getMemberCount());
 		
-		packet.writeD(_channel.getPartys().size());
+		packet.writeD(_channel.getParties().size());
-		for (Party p : _channel.getPartys())
+		for (Party p : _channel.getParties())
 		{
 			packet.writeS(p.getLeader().getName());
 			packet.writeD(p.getLeaderObjectId());

L2J_Mobius_2.5_Underground/java/org/l2jmobius/gameserver/taskmanager/TaskManager.java

@@ -26,11 +26,10 @@ import java.sql.ResultSet;
 import java.sql.SQLException;
 import java.text.DateFormat;
 import java.util.Calendar;
+import java.util.Collection;
 import java.util.Date;
-import java.util.List;
 import java.util.Map;
 import java.util.concurrent.ConcurrentHashMap;
-import java.util.concurrent.CopyOnWriteArrayList;
 import java.util.concurrent.ScheduledFuture;
 import java.util.logging.Level;
 import java.util.logging.Logger;
@@ -50,7 +49,7 @@ public class TaskManager
 	static final Logger LOGGER = Logger.getLogger(TaskManager.class.getName());
 	
 	private final Map<Integer, Task> _tasks = new ConcurrentHashMap<>();
-	final List<ExecutedTask> _currentTasks = new CopyOnWriteArrayList<>();
+	final Collection<ExecutedTask> _currentTasks = ConcurrentHashMap.newKeySet();
 	
 	static final String[] SQL_STATEMENTS =
 	{

L2J_Mobius_2.5_Underground/java/org/l2jmobius/loginserver/GameServerListener.java

@@ -18,8 +18,8 @@ package org.l2jmobius.loginserver;
 
 import java.io.IOException;
 import java.net.Socket;
-import java.util.List;
+import java.util.Collection;
-import java.util.concurrent.CopyOnWriteArrayList;
+import java.util.concurrent.ConcurrentHashMap;
 
 import org.l2jmobius.Config;
 
@@ -28,7 +28,7 @@ import org.l2jmobius.Config;
  */
 public class GameServerListener extends FloodProtectedListener
 {
-	private static List<GameServerThread> _gameServers = new CopyOnWriteArrayList<>();
+	private static Collection<GameServerThread> _gameServers = ConcurrentHashMap.newKeySet();
 	
 	public GameServerListener() throws IOException
 	{

L2J_Mobius_3.0_Helios/dist/game/data/scripts/ai/areas/FantasyIsle/Parade.java

@@ -17,7 +17,8 @@
 package ai.areas.FantasyIsle;
 
 import java.text.SimpleDateFormat;
-import java.util.concurrent.CopyOnWriteArrayList;
+import java.util.Collection;
+import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.ScheduledFuture;
 
 import org.l2jmobius.commons.concurrent.ThreadPool;
@@ -120,7 +121,7 @@ public class Parade extends AbstractNpcAI
 	// @formatter:on
 	
 	int npcIndex;
-	CopyOnWriteArrayList<Npc> spawns = new CopyOnWriteArrayList<>();
+	Collection<Npc> spawns = ConcurrentHashMap.newKeySet();
 	ScheduledFuture<?> spawnTask;
 	ScheduledFuture<?> deleteTask;
 	ScheduledFuture<?> cleanTask;

L2J_Mobius_3.0_Helios/dist/game/data/scripts/ai/bosses/Core/Core.java

@@ -16,11 +16,11 @@
  */
 package ai.bosses.Core;
 
+import java.util.Collection;
 import java.util.HashMap;
-import java.util.List;
 import java.util.Map;
 import java.util.Map.Entry;
-import java.util.concurrent.CopyOnWriteArrayList;
+import java.util.concurrent.ConcurrentHashMap;
 
 import org.l2jmobius.Config;
 import org.l2jmobius.gameserver.enums.ChatType;
@@ -78,7 +78,7 @@ public class Core extends AbstractNpcAI
 	
 	private static boolean _firstAttacked;
 	
-	private static final List<Attackable> _minions = new CopyOnWriteArrayList<>();
+	private static final Collection<Attackable> _minions = ConcurrentHashMap.newKeySet();
 	
 	private Core()
 	{

L2J_Mobius_3.0_Helios/dist/game/data/scripts/ai/others/SiegeGuards.java

@@ -16,8 +16,8 @@
  */
 package ai.others;
 
-import java.util.List;
+import java.util.Collection;
-import java.util.concurrent.CopyOnWriteArrayList;
+import java.util.concurrent.ConcurrentHashMap;
 
 import org.l2jmobius.gameserver.ai.CtrlIntention;
 import org.l2jmobius.gameserver.geoengine.GeoEngine;
@@ -87,7 +87,7 @@ public class SiegeGuards extends AbstractNpcAI
 		35134, 35135, 35136, 35176, 35177, 35178, 35218, 35219, 35220, 35261, 35262, 35263, 35264, 35265, 35308, 35309, 35310, 35352, 35353, 35354, 35497, 35498, 35499, 35500, 35501, 35544, 35545, 35546
 	};
 	//@formatter:on
-	private static final List<Npc> SPAWNED_GUARDS = new CopyOnWriteArrayList<>();
+	private static final Collection<Npc> SPAWNED_GUARDS = ConcurrentHashMap.newKeySet();
 	
 	public SiegeGuards()
 	{

L2J_Mobius_3.0_Helios/dist/game/data/scripts/custom/events/Rabbits/Rabbits.java

@@ -17,8 +17,9 @@
 package custom.events.Rabbits;
 
 import java.util.ArrayList;
+import java.util.Collection;
 import java.util.List;
-import java.util.concurrent.CopyOnWriteArrayList;
+import java.util.concurrent.ConcurrentHashMap;
 
 import org.l2jmobius.Config;
 import org.l2jmobius.commons.util.CommonUtil;
@@ -49,7 +50,7 @@ public class Rabbits extends Event
 	private static final int EVENT_TIME = 10;
 	private static final int TOTAL_CHEST_COUNT = 75;
 	private static final int TRANSFORMATION_ID = 105;
-	private final List<Npc> _npcs = new CopyOnWriteArrayList<>();
+	private final Collection<Npc> _npcs = ConcurrentHashMap.newKeySet();
 	private final List<PlayerInstance> _players = new ArrayList<>();
 	private boolean _isActive = false;
 	
@@ -253,7 +254,7 @@ public class Rabbits extends Event
 		}
 	}
 	
-	private void recordSpawn(List<Npc> npcs, int npcId, int x, int y, int z, int heading, boolean randomOffSet, long despawnDelay)
+	private void recordSpawn(Collection<Npc> npcs, int npcId, int x, int y, int z, int heading, boolean randomOffSet, long despawnDelay)
 	{
 		final Npc npc = addSpawn(npcId, x, y, z, heading, randomOffSet, despawnDelay);
 		if (npc.getId() == CHEST)

L2J_Mobius_3.0_Helios/dist/game/data/scripts/custom/events/Race/Race.java

@@ -17,8 +17,9 @@
 package custom.events.Race;
 
 import java.util.ArrayList;
+import java.util.Collection;
 import java.util.List;
-import java.util.concurrent.CopyOnWriteArrayList;
+import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.ScheduledFuture;
 
 import org.l2jmobius.Config;
@@ -45,7 +46,7 @@ public class Race extends Event
 	// Npc
 	private Npc _npc;
 	// Player list
-	private List<PlayerInstance> _players;
+	private Collection<PlayerInstance> _players;
 	// Event Task
 	ScheduledFuture<?> _eventTask = null;
 	// Event state
@@ -127,7 +128,7 @@ public class Race extends Event
 		}
 		// Initialize list
 		_npclist = new ArrayList<>();
-		_players = new CopyOnWriteArrayList<>();
+		_players = ConcurrentHashMap.newKeySet();
 		// Set Event active
 		_isactive = true;
 		// Spawn Manager

L2J_Mobius_3.0_Helios/java/org/l2jmobius/commons/util/IXmlReader.java

@@ -19,11 +19,12 @@ package org.l2jmobius.commons.util;
 import java.io.File;
 import java.io.FileFilter;
 import java.util.ArrayList;
+import java.util.Collection;
 import java.util.HashMap;
 import java.util.LinkedHashMap;
 import java.util.List;
 import java.util.Map;
-import java.util.concurrent.CopyOnWriteArrayList;
+import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.ScheduledFuture;
 import java.util.function.Consumer;
 import java.util.function.Predicate;
@@ -167,7 +168,7 @@ public interface IXmlReader
 		
 		if (Config.THREADS_FOR_LOADING)
 		{
-			final List<ScheduledFuture<?>> jobs = new CopyOnWriteArrayList<>();
+			final Collection<ScheduledFuture<?>> jobs = ConcurrentHashMap.newKeySet();
 			final File[] listOfFiles = dir.listFiles();
 			for (File file : listOfFiles)
 			{

L2J_Mobius_3.0_Helios/java/org/l2jmobius/gameserver/communitybbs/BB/Forum.java

@@ -19,10 +19,9 @@ package org.l2jmobius.gameserver.communitybbs.BB;
 import java.sql.Connection;
 import java.sql.PreparedStatement;
 import java.sql.ResultSet;
-import java.util.List;
+import java.util.Collection;
 import java.util.Map;
 import java.util.concurrent.ConcurrentHashMap;
-import java.util.concurrent.CopyOnWriteArrayList;
 import java.util.logging.Level;
 import java.util.logging.Logger;
 
@@ -46,7 +45,7 @@ public class Forum
 	public static final int CLANMEMBERONLY = 2;
 	public static final int OWNERONLY = 3;
 	
-	private final List<Forum> _children;
+	private final Collection<Forum> _children;
 	private final Map<Integer, Topic> _topic = new ConcurrentHashMap<>();
 	private final int _forumId;
 	private String _forumName;
@@ -66,7 +65,7 @@ public class Forum
 	{
 		_forumId = Forumid;
 		_fParent = FParent;
-		_children = new CopyOnWriteArrayList<>();
+		_children = ConcurrentHashMap.newKeySet();
 	}
 	
 	/**
@@ -85,7 +84,7 @@ public class Forum
 		_forumPerm = perm;
 		_fParent = parent;
 		_ownerID = OwnerID;
-		_children = new CopyOnWriteArrayList<>();
+		_children = ConcurrentHashMap.newKeySet();
 		parent._children.add(this);
 		ForumsBBSManager.getInstance().addForum(this);
 		_loaded = true;

L2J_Mobius_3.0_Helios/java/org/l2jmobius/gameserver/communitybbs/BB/Post.java

@@ -19,8 +19,8 @@ package org.l2jmobius.gameserver.communitybbs.BB;
 import java.sql.Connection;
 import java.sql.PreparedStatement;
 import java.sql.ResultSet;
-import java.util.List;
+import java.util.Collection;
-import java.util.concurrent.CopyOnWriteArrayList;
+import java.util.concurrent.ConcurrentHashMap;
 import java.util.logging.Level;
 import java.util.logging.Logger;
 
@@ -45,7 +45,7 @@ public class Post
 		public String postTxt;
 	}
 	
-	private final List<CPost> _post;
+	private final Collection<CPost> _post;
 	
 	/**
 	 * @param _PostOwner
@@ -57,7 +57,7 @@ public class Post
 	 */
 	public Post(String _PostOwner, int _PostOwnerID, long date, int tid, int _PostForumID, String txt)
 	{
-		_post = new CopyOnWriteArrayList<>();
+		_post = ConcurrentHashMap.newKeySet();
 		final CPost cp = new CPost();
 		cp.postId = 0;
 		cp.postOwner = _PostOwner;
@@ -92,7 +92,7 @@ public class Post
 	
 	public Post(Topic t)
 	{
-		_post = new CopyOnWriteArrayList<>();
+		_post = ConcurrentHashMap.newKeySet();
 		load(t);
 	}
 	

L2J_Mobius_3.0_Helios/java/org/l2jmobius/gameserver/communitybbs/Manager/ForumsBBSManager.java

@@ -19,8 +19,8 @@ package org.l2jmobius.gameserver.communitybbs.Manager;
 import java.sql.Connection;
 import java.sql.ResultSet;
 import java.sql.Statement;
-import java.util.List;
+import java.util.Collection;
-import java.util.concurrent.CopyOnWriteArrayList;
+import java.util.concurrent.ConcurrentHashMap;
 import java.util.logging.Level;
 import java.util.logging.Logger;
 
@@ -31,7 +31,7 @@ import org.l2jmobius.gameserver.model.actor.instance.PlayerInstance;
 public class ForumsBBSManager extends BaseBBSManager
 {
 	private static Logger LOGGER = Logger.getLogger(ForumsBBSManager.class.getName());
-	private final List<Forum> _table;
+	private final Collection<Forum> _table;
 	private int _lastid = 1;
 	
 	/**
@@ -39,7 +39,7 @@ public class ForumsBBSManager extends BaseBBSManager
 	 */
 	protected ForumsBBSManager()
 	{
-		_table = new CopyOnWriteArrayList<>();
+		_table = ConcurrentHashMap.newKeySet();
 		try (Connection con = DatabaseFactory.getConnection();
 			Statement s = con.createStatement();
 			ResultSet rs = s.executeQuery("SELECT forum_id FROM forums WHERE forum_type = 0"))

L2J_Mobius_3.0_Helios/java/org/l2jmobius/gameserver/communitybbs/Manager/TopicBBSManager.java

@@ -18,12 +18,11 @@ package org.l2jmobius.gameserver.communitybbs.Manager;
 
 import java.text.DateFormat;
 import java.util.Calendar;
+import java.util.Collection;
 import java.util.Date;
-import java.util.List;
 import java.util.Map;
 import java.util.StringTokenizer;
 import java.util.concurrent.ConcurrentHashMap;
-import java.util.concurrent.CopyOnWriteArrayList;
 
 import org.l2jmobius.gameserver.communitybbs.BB.Forum;
 import org.l2jmobius.gameserver.communitybbs.BB.Post;
@@ -34,7 +33,7 @@ import org.l2jmobius.gameserver.model.actor.instance.PlayerInstance;
 
 public class TopicBBSManager extends BaseBBSManager
 {
-	private final List<Topic> _table = new CopyOnWriteArrayList<>();
+	private final Collection<Topic> _table = ConcurrentHashMap.newKeySet();
 	private final Map<Forum, Integer> _maxId = new ConcurrentHashMap<>();
 	
 	protected TopicBBSManager()

L2J_Mobius_3.0_Helios/java/org/l2jmobius/gameserver/data/xml/impl/NpcData.java

@@ -18,6 +18,7 @@ package org.l2jmobius.gameserver.data.xml.impl;
 
 import java.io.File;
 import java.util.ArrayList;
+import java.util.Collection;
 import java.util.Collections;
 import java.util.EnumMap;
 import java.util.HashMap;
@@ -27,7 +28,6 @@ import java.util.Map;
 import java.util.Map.Entry;
 import java.util.Set;
 import java.util.concurrent.ConcurrentHashMap;
-import java.util.concurrent.CopyOnWriteArrayList;
 import java.util.function.Predicate;
 import java.util.logging.Logger;
 import java.util.stream.Collectors;
@@ -60,7 +60,7 @@ public class NpcData implements IXmlReader
 	
 	private final Map<Integer, NpcTemplate> _npcs = new ConcurrentHashMap<>();
 	private final Map<String, Integer> _clans = new ConcurrentHashMap<>();
-	private static final List<Integer> _masterMonsterIDs = new CopyOnWriteArrayList<>();
+	private static final Collection<Integer> _masterMonsterIDs = ConcurrentHashMap.newKeySet();
 	
 	protected NpcData()
 	{
@@ -789,7 +789,7 @@ public class NpcData implements IXmlReader
 	/**
 	 * @return the IDs of monsters that have minions.
 	 */
-	public static List<Integer> getMasterMonsterIDs()
+	public static Collection<Integer> getMasterMonsterIDs()
 	{
 		return _masterMonsterIDs;
 	}

L2J_Mobius_3.0_Helios/java/org/l2jmobius/gameserver/data/xml/impl/SpawnsData.java

@@ -18,10 +18,11 @@ package org.l2jmobius.gameserver.data.xml.impl;
 
 import java.io.File;
 import java.util.ArrayList;
+import java.util.Collection;
 import java.util.Collections;
 import java.util.List;
 import java.util.Map;
-import java.util.concurrent.CopyOnWriteArrayList;
+import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.ScheduledFuture;
 import java.util.function.Predicate;
 import java.util.logging.Level;
@@ -54,7 +55,7 @@ public class SpawnsData implements IXmlReader
 {
 	protected static final Logger LOGGER = Logger.getLogger(SpawnsData.class.getName());
 	
-	private final List<SpawnTemplate> _spawns = new CopyOnWriteArrayList<>();
+	private final Collection<SpawnTemplate> _spawns = ConcurrentHashMap.newKeySet();
 	
 	protected SpawnsData()
 	{
@@ -98,7 +99,7 @@ public class SpawnsData implements IXmlReader
 		
 		if (Config.THREADS_FOR_LOADING)
 		{
-			final List<ScheduledFuture<?>> jobs = new CopyOnWriteArrayList<>();
+			final Collection<ScheduledFuture<?>> jobs = ConcurrentHashMap.newKeySet();
 			for (SpawnTemplate template : _spawns)
 			{
 				if (template.isSpawningByDefault())
@@ -146,7 +147,7 @@ public class SpawnsData implements IXmlReader
 		LOGGER.info(getClass().getSimpleName() + ": All spawns has been removed!");
 	}
 	
-	public List<SpawnTemplate> getSpawns()
+	public Collection<SpawnTemplate> getSpawns()
 	{
 		return _spawns;
 	}
@@ -166,7 +167,7 @@ public class SpawnsData implements IXmlReader
 		return _spawns.stream().flatMap(template -> template.getGroups().stream()).flatMap(group -> group.getSpawns().stream()).filter(condition).collect(Collectors.toList());
 	}
 	
-	public void parseSpawn(Node spawnsNode, File file, List<SpawnTemplate> spawns)
+	public void parseSpawn(Node spawnsNode, File file, Collection<SpawnTemplate> spawns)
 	{
 		final SpawnTemplate spawnTemplate = new SpawnTemplate(new StatsSet(parseAttributes(spawnsNode)), file);
 		SpawnGroup defaultGroup = null;

L2J_Mobius_3.0_Helios/java/org/l2jmobius/gameserver/datatables/EventDroplist.java

@@ -16,10 +16,11 @@
  */
 package org.l2jmobius.gameserver.datatables;
 
+import java.util.Collection;
 import java.util.Date;
 import java.util.LinkedList;
 import java.util.List;
-import java.util.concurrent.CopyOnWriteArrayList;
+import java.util.concurrent.ConcurrentHashMap;
 
 import org.l2jmobius.gameserver.script.DateRange;
 import org.l2jmobius.gameserver.script.EventDrop;
@@ -35,7 +36,7 @@ public class EventDroplist
 	/**
 	 * The table containing all DataDrop object
 	 */
-	private static final List<DateDrop> ALL_NPC_DATE_DROPS = new CopyOnWriteArrayList<>();
+	private static final Collection<DateDrop> ALL_NPC_DATE_DROPS = ConcurrentHashMap.newKeySet();
 	
 	public static class DateDrop
 	{

L2J_Mobius_3.0_Helios/java/org/l2jmobius/gameserver/engines/DocumentEngine.java

@@ -18,8 +18,9 @@ package org.l2jmobius.gameserver.engines;
 
 import java.io.File;
 import java.util.ArrayList;
+import java.util.Collection;
 import java.util.List;
-import java.util.concurrent.CopyOnWriteArrayList;
+import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.ScheduledFuture;
 import java.util.logging.Logger;
 
@@ -66,13 +67,13 @@ public class DocumentEngine
 	 * Return created items
 	 * @return List of {@link Item}
 	 */
-	public List<Item> loadItems()
+	public Collection<Item> loadItems()
 	{
-		final List<Item> list = new CopyOnWriteArrayList<>();
+		final Collection<Item> list = ConcurrentHashMap.newKeySet();
 		
 		if (Config.THREADS_FOR_LOADING)
 		{
-			final List<ScheduledFuture<?>> jobs = new CopyOnWriteArrayList<>();
+			final Collection<ScheduledFuture<?>> jobs = ConcurrentHashMap.newKeySet();
 			for (File file : _itemFiles)
 			{
 				jobs.add(ThreadPool.schedule(() ->

L2J_Mobius_3.0_Helios/java/org/l2jmobius/gameserver/model/CommandChannel.java

@@ -16,9 +16,10 @@
  */
 package org.l2jmobius.gameserver.model;
 
+import java.util.Collection;
 import java.util.LinkedList;
 import java.util.List;
-import java.util.concurrent.CopyOnWriteArrayList;
+import java.util.concurrent.ConcurrentHashMap;
 import java.util.function.Function;
 
 import org.l2jmobius.Config;
@@ -36,7 +37,7 @@ import org.l2jmobius.gameserver.network.serverpackets.SystemMessage;
  */
 public class CommandChannel extends AbstractPlayerGroup
 {
-	private final List<Party> _parties = new CopyOnWriteArrayList<>();
+	private final Collection<Party> _parties = ConcurrentHashMap.newKeySet();
 	private PlayerInstance _commandLeader;
 	private int _channelLvl;
 	
@@ -150,7 +151,7 @@ public class CommandChannel extends AbstractPlayerGroup
 	/**
 	 * @return a list of all parties in this command channel
 	 */
-	public List<Party> getPartys()
+	public Collection<Party> getParties()
 	{
 		return _parties;
 	}

L2J_Mobius_3.0_Helios/java/org/l2jmobius/gameserver/model/Petition.java

@@ -16,8 +16,8 @@
  */
 package org.l2jmobius.gameserver.model;
 
-import java.util.List;
+import java.util.Collection;
-import java.util.concurrent.CopyOnWriteArrayList;
+import java.util.concurrent.ConcurrentHashMap;
 
 import org.l2jmobius.gameserver.enums.PetitionState;
 import org.l2jmobius.gameserver.enums.PetitionType;
@@ -41,7 +41,7 @@ public class Petition
 	private final PetitionType _type;
 	private PetitionState _state = PetitionState.PENDING;
 	private final String _content;
-	private final List<CreatureSay> _messageLog = new CopyOnWriteArrayList<>();
+	private final Collection<CreatureSay> _messageLog = ConcurrentHashMap.newKeySet();
 	private final PlayerInstance _petitioner;
 	private PlayerInstance _responder;
 	
@@ -58,7 +58,7 @@ public class Petition
 		return _messageLog.add(cs);
 	}
 	
-	public List<CreatureSay> getLogMessages()
+	public Collection<CreatureSay> getLogMessages()
 	{
 		return _messageLog;
 	}

L2J_Mobius_3.0_Helios/java/org/l2jmobius/gameserver/model/actor/instance/RaceManagerInstance.java

@@ -16,8 +16,8 @@
  */
 package org.l2jmobius.gameserver.model.actor.instance;
 
-import java.util.List;
+import java.util.Collection;
-import java.util.concurrent.CopyOnWriteArrayList;
+import java.util.concurrent.ConcurrentHashMap;
 
 import org.l2jmobius.Config;
 import org.l2jmobius.commons.concurrent.ThreadPool;
@@ -45,7 +45,7 @@ public class RaceManagerInstance extends Npc
 	public static final int LANES = 8;
 	public static final int WINDOW_START = 0;
 	
-	private static List<RaceManagerInstance> _managers;
+	private static Collection<RaceManagerInstance> _managers;
 	protected static int _raceNumber = 4;
 	
 	// Time Constants
@@ -104,7 +104,7 @@ public class RaceManagerInstance extends Npc
 		{
 			_notInitialized = false;
 			
-			_managers = new CopyOnWriteArrayList<>();
+			_managers = ConcurrentHashMap.newKeySet();
 			
 			ThreadPool.scheduleAtFixedRate(new Announcement(SystemMessageId.TICKETS_ARE_NOW_AVAILABLE_FOR_MONSTER_RACE_S1), 0, 10 * MINUTE);
 			ThreadPool.scheduleAtFixedRate(new Announcement(SystemMessageId.NOW_SELLING_TICKETS_FOR_MONSTER_RACE_S1), 30 * SECOND, 10 * MINUTE);

L2J_Mobius_3.0_Helios/java/org/l2jmobius/gameserver/model/actor/instance/ServitorInstance.java

@@ -19,10 +19,12 @@ package org.l2jmobius.gameserver.model.actor.instance;
 import java.sql.Connection;
 import java.sql.PreparedStatement;
 import java.sql.ResultSet;
+import java.util.Collection;
 import java.util.Collections;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.CopyOnWriteArrayList;
 import java.util.concurrent.Future;
 import java.util.logging.Level;
@@ -304,7 +306,7 @@ public class ServitorInstance extends Summon implements Runnable
 			
 			int buff_index = 0;
 			
-			final List<Long> storedSkills = new CopyOnWriteArrayList<>();
+			final Collection<Long> storedSkills = ConcurrentHashMap.newKeySet();
 			
 			// Store all effect data along with calculated remaining
 			if (storeEffects)

L2J_Mobius_3.0_Helios/java/org/l2jmobius/gameserver/model/actor/instance/TamedBeastInstance.java

@@ -18,8 +18,8 @@ package org.l2jmobius.gameserver.model.actor.instance;
 
 import static org.l2jmobius.gameserver.ai.CtrlIntention.AI_INTENTION_IDLE;
 
-import java.util.List;
+import java.util.Collection;
-import java.util.concurrent.CopyOnWriteArrayList;
+import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.Future;
 
 import org.l2jmobius.commons.concurrent.ThreadPool;
@@ -62,7 +62,7 @@ public class TamedBeastInstance extends FeedableBeastInstance
 	private Future<?> _buffTask = null;
 	private Future<?> _durationCheckTask = null;
 	protected boolean _isFreyaBeast;
-	private List<Skill> _beastSkills = null;
+	private Collection<Skill> _beastSkills = null;
 	
 	public TamedBeastInstance(int npcTemplateId)
 	{
@@ -205,7 +205,7 @@ public class TamedBeastInstance extends FeedableBeastInstance
 	{
 		if (_beastSkills == null)
 		{
-			_beastSkills = new CopyOnWriteArrayList<>();
+			_beastSkills = ConcurrentHashMap.newKeySet();
 		}
 		_beastSkills.add(skill);
 	}

L2J_Mobius_3.0_Helios/java/org/l2jmobius/gameserver/model/entity/Siegable.java

@@ -49,7 +49,7 @@ public interface Siegable
 	
 	SiegeClan getDefenderClan(Clan clan);
 	
-	List<SiegeClan> getDefenderClans();
+	Collection<SiegeClan> getDefenderClans();
 	
 	boolean checkIsDefender(Clan clan);
 	

L2J_Mobius_3.0_Helios/java/org/l2jmobius/gameserver/model/entity/Siege.java

@@ -21,12 +21,13 @@ import java.sql.PreparedStatement;
 import java.sql.ResultSet;
 import java.util.ArrayList;
 import java.util.Calendar;
+import java.util.Collection;
 import java.util.Collections;
 import java.util.Iterator;
 import java.util.List;
 import java.util.Objects;
 import java.util.Set;
-import java.util.concurrent.CopyOnWriteArrayList;
+import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.ScheduledFuture;
 import java.util.logging.Level;
 import java.util.logging.Logger;
@@ -221,9 +222,9 @@ public class Siege implements Siegable
 	}
 	
 	// must support Concurrent Modifications
-	private final List<SiegeClan> _attackerClans = new CopyOnWriteArrayList<>();
+	private final Collection<SiegeClan> _attackerClans = ConcurrentHashMap.newKeySet();
-	private final List<SiegeClan> _defenderClans = new CopyOnWriteArrayList<>();
+	private final Collection<SiegeClan> _defenderClans = ConcurrentHashMap.newKeySet();
-	private final List<SiegeClan> _defenderWaitingClans = new CopyOnWriteArrayList<>();
+	private final Collection<SiegeClan> _defenderWaitingClans = ConcurrentHashMap.newKeySet();
 	
 	// Castle setting
 	private final List<ControlTowerInstance> _controlTowers = new ArrayList<>();
@@ -1582,7 +1583,7 @@ public class Siege implements Siegable
 	}
 	
 	@Override
-	public List<SiegeClan> getAttackerClans()
+	public Collection<SiegeClan> getAttackerClans()
 	{
 		if (_isNormalSide)
 		{
@@ -1625,7 +1626,7 @@ public class Siege implements Siegable
 	}
 	
 	@Override
-	public List<SiegeClan> getDefenderClans()
+	public Collection<SiegeClan> getDefenderClans()
 	{
 		if (_isNormalSide)
 		{
@@ -1655,7 +1656,7 @@ public class Siege implements Siegable
 		return null;
 	}
 	
-	public List<SiegeClan> getDefenderWaitingClans()
+	public Collection<SiegeClan> getDefenderWaitingClans()
 	{
 		return _defenderWaitingClans;
 	}

L2J_Mobius_3.0_Helios/java/org/l2jmobius/gameserver/model/holders/MovieHolder.java

@@ -16,8 +16,9 @@
  */
 package org.l2jmobius.gameserver.model.holders;
 
+import java.util.Collection;
 import java.util.List;
-import java.util.concurrent.CopyOnWriteArrayList;
+import java.util.concurrent.ConcurrentHashMap;
 
 import org.l2jmobius.gameserver.enums.Movie;
 import org.l2jmobius.gameserver.model.actor.instance.PlayerInstance;
@@ -29,7 +30,7 @@ public class MovieHolder
 {
 	private final Movie _movie;
 	private final List<PlayerInstance> _players;
-	private final List<PlayerInstance> _votedPlayers = new CopyOnWriteArrayList<>();
+	private final Collection<PlayerInstance> _votedPlayers = ConcurrentHashMap.newKeySet();
 	
 	public MovieHolder(List<PlayerInstance> players, Movie movie)
 	{
@@ -64,7 +65,7 @@ public class MovieHolder
 		return _players;
 	}
 	
-	public List<PlayerInstance> getVotedPlayers()
+	public Collection<PlayerInstance> getVotedPlayers()
 	{
 		return _votedPlayers;
 	}

L2J_Mobius_3.0_Helios/java/org/l2jmobius/gameserver/model/matching/CommandChannelMatchingRoom.java

@@ -127,7 +127,7 @@ public class CommandChannelMatchingRoom extends MatchingRoom
 		if (leaderParty != null)
 		{
 			final CommandChannel cc = leaderParty.getCommandChannel();
-			if ((leaderParty == playerParty) || ((cc != null) && cc.getPartys().contains(playerParty)))
+			if ((leaderParty == playerParty) || ((cc != null) && cc.getParties().contains(playerParty)))
 			{
 				return MatchingMemberType.COMMAND_CHANNEL_PARTY_MEMBER;
 			}

L2J_Mobius_3.0_Helios/java/org/l2jmobius/gameserver/network/serverpackets/ExMultiPartyCommandChannelInfo.java

@@ -45,8 +45,8 @@ public class ExMultiPartyCommandChannelInfo implements IClientOutgoingPacket
 		packet.writeD(0x00); // Channel loot 0 or 1
 		packet.writeD(_channel.getMemberCount());
 		
-		packet.writeD(_channel.getPartys().size());
+		packet.writeD(_channel.getParties().size());
-		for (Party p : _channel.getPartys())
+		for (Party p : _channel.getParties())
 		{
 			packet.writeS(p.getLeader().getName());
 			packet.writeD(p.getLeaderObjectId());

L2J_Mobius_3.0_Helios/java/org/l2jmobius/gameserver/taskmanager/TaskManager.java

@@ -26,11 +26,10 @@ import java.sql.ResultSet;
 import java.sql.SQLException;
 import java.text.DateFormat;
 import java.util.Calendar;
+import java.util.Collection;
 import java.util.Date;
-import java.util.List;
 import java.util.Map;
 import java.util.concurrent.ConcurrentHashMap;
-import java.util.concurrent.CopyOnWriteArrayList;
 import java.util.concurrent.ScheduledFuture;
 import java.util.logging.Level;
 import java.util.logging.Logger;
@@ -50,7 +49,7 @@ public class TaskManager
 	static final Logger LOGGER = Logger.getLogger(TaskManager.class.getName());
 	
 	private final Map<Integer, Task> _tasks = new ConcurrentHashMap<>();
-	final List<ExecutedTask> _currentTasks = new CopyOnWriteArrayList<>();
+	final Collection<ExecutedTask> _currentTasks = ConcurrentHashMap.newKeySet();
 	
 	static final String[] SQL_STATEMENTS =
 	{

L2J_Mobius_3.0_Helios/java/org/l2jmobius/loginserver/GameServerListener.java

@@ -18,8 +18,8 @@ package org.l2jmobius.loginserver;
 
 import java.io.IOException;
 import java.net.Socket;
-import java.util.List;
+import java.util.Collection;
-import java.util.concurrent.CopyOnWriteArrayList;
+import java.util.concurrent.ConcurrentHashMap;
 
 import org.l2jmobius.Config;
 
@@ -28,7 +28,7 @@ import org.l2jmobius.Config;
  */
 public class GameServerListener extends FloodProtectedListener
 {
-	private static List<GameServerThread> _gameServers = new CopyOnWriteArrayList<>();
+	private static Collection<GameServerThread> _gameServers = ConcurrentHashMap.newKeySet();
 	
 	public GameServerListener() throws IOException
 	{

L2J_Mobius_4.0_GrandCrusade/dist/game/data/scripts/ai/areas/FantasyIsle/Parade.java

@@ -17,7 +17,8 @@
 package ai.areas.FantasyIsle;
 
 import java.text.SimpleDateFormat;
-import java.util.concurrent.CopyOnWriteArrayList;
+import java.util.Collection;
+import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.ScheduledFuture;
 
 import org.l2jmobius.commons.concurrent.ThreadPool;
@@ -120,7 +121,7 @@ public class Parade extends AbstractNpcAI
 	// @formatter:on
 	
 	int npcIndex;
-	CopyOnWriteArrayList<Npc> spawns = new CopyOnWriteArrayList<>();
+	Collection<Npc> spawns = ConcurrentHashMap.newKeySet();
 	ScheduledFuture<?> spawnTask;
 	ScheduledFuture<?> deleteTask;
 	ScheduledFuture<?> cleanTask;

L2J_Mobius_4.0_GrandCrusade/dist/game/data/scripts/ai/bosses/Core/Core.java

@@ -16,11 +16,11 @@
  */
 package ai.bosses.Core;
 
+import java.util.Collection;
 import java.util.HashMap;
-import java.util.List;
 import java.util.Map;
 import java.util.Map.Entry;
-import java.util.concurrent.CopyOnWriteArrayList;
+import java.util.concurrent.ConcurrentHashMap;
 
 import org.l2jmobius.Config;
 import org.l2jmobius.gameserver.enums.ChatType;
@@ -78,7 +78,7 @@ public class Core extends AbstractNpcAI
 	
 	private static boolean _firstAttacked;
 	
-	private static final List<Attackable> _minions = new CopyOnWriteArrayList<>();
+	private static final Collection<Attackable> _minions = ConcurrentHashMap.newKeySet();
 	
 	private Core()
 	{

L2J_Mobius_4.0_GrandCrusade/dist/game/data/scripts/ai/others/SiegeGuards.java

@@ -16,8 +16,8 @@
  */
 package ai.others;
 
-import java.util.List;
+import java.util.Collection;
-import java.util.concurrent.CopyOnWriteArrayList;
+import java.util.concurrent.ConcurrentHashMap;
 
 import org.l2jmobius.gameserver.ai.CtrlIntention;
 import org.l2jmobius.gameserver.geoengine.GeoEngine;
@@ -87,7 +87,7 @@ public class SiegeGuards extends AbstractNpcAI
 		35134, 35135, 35136, 35176, 35177, 35178, 35218, 35219, 35220, 35261, 35262, 35263, 35264, 35265, 35308, 35309, 35310, 35352, 35353, 35354, 35497, 35498, 35499, 35500, 35501, 35544, 35545, 35546
 	};
 	//@formatter:on
-	private static final List<Npc> SPAWNED_GUARDS = new CopyOnWriteArrayList<>();
+	private static final Collection<Npc> SPAWNED_GUARDS = ConcurrentHashMap.newKeySet();
 	
 	public SiegeGuards()
 	{

L2J_Mobius_4.0_GrandCrusade/dist/game/data/scripts/custom/events/Rabbits/Rabbits.java

@@ -17,8 +17,9 @@
 package custom.events.Rabbits;
 
 import java.util.ArrayList;
+import java.util.Collection;
 import java.util.List;
-import java.util.concurrent.CopyOnWriteArrayList;
+import java.util.concurrent.ConcurrentHashMap;
 
 import org.l2jmobius.Config;
 import org.l2jmobius.commons.util.CommonUtil;
@@ -49,7 +50,7 @@ public class Rabbits extends Event
 	private static final int EVENT_TIME = 10;
 	private static final int TOTAL_CHEST_COUNT = 75;
 	private static final int TRANSFORMATION_ID = 105;
-	private final List<Npc> _npcs = new CopyOnWriteArrayList<>();
+	private final Collection<Npc> _npcs = ConcurrentHashMap.newKeySet();
 	private final List<PlayerInstance> _players = new ArrayList<>();
 	private boolean _isActive = false;
 	
@@ -253,7 +254,7 @@ public class Rabbits extends Event
 		}
 	}
 	
-	private void recordSpawn(List<Npc> npcs, int npcId, int x, int y, int z, int heading, boolean randomOffSet, long despawnDelay)
+	private void recordSpawn(Collection<Npc> npcs, int npcId, int x, int y, int z, int heading, boolean randomOffSet, long despawnDelay)
 	{
 		final Npc npc = addSpawn(npcId, x, y, z, heading, randomOffSet, despawnDelay);
 		if (npc.getId() == CHEST)

L2J_Mobius_4.0_GrandCrusade/dist/game/data/scripts/custom/events/Race/Race.java

@@ -17,8 +17,9 @@
 package custom.events.Race;
 
 import java.util.ArrayList;
+import java.util.Collection;
 import java.util.List;
-import java.util.concurrent.CopyOnWriteArrayList;
+import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.ScheduledFuture;
 
 import org.l2jmobius.Config;
@@ -45,7 +46,7 @@ public class Race extends Event
 	// Npc
 	private Npc _npc;
 	// Player list
-	private List<PlayerInstance> _players;
+	private Collection<PlayerInstance> _players;
 	// Event Task
 	ScheduledFuture<?> _eventTask = null;
 	// Event state
@@ -127,7 +128,7 @@ public class Race extends Event
 		}
 		// Initialize list
 		_npclist = new ArrayList<>();
-		_players = new CopyOnWriteArrayList<>();
+		_players = ConcurrentHashMap.newKeySet();
 		// Set Event active
 		_isactive = true;
 		// Spawn Manager

L2J_Mobius_4.0_GrandCrusade/java/org/l2jmobius/commons/util/IXmlReader.java

@@ -19,11 +19,12 @@ package org.l2jmobius.commons.util;
 import java.io.File;
 import java.io.FileFilter;
 import java.util.ArrayList;
+import java.util.Collection;
 import java.util.HashMap;
 import java.util.LinkedHashMap;
 import java.util.List;
 import java.util.Map;
-import java.util.concurrent.CopyOnWriteArrayList;
+import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.ScheduledFuture;
 import java.util.function.Consumer;
 import java.util.function.Predicate;
@@ -167,7 +168,7 @@ public interface IXmlReader
 		
 		if (Config.THREADS_FOR_LOADING)
 		{
-			final List<ScheduledFuture<?>> jobs = new CopyOnWriteArrayList<>();
+			final Collection<ScheduledFuture<?>> jobs = ConcurrentHashMap.newKeySet();
 			final File[] listOfFiles = dir.listFiles();
 			for (File file : listOfFiles)
 			{

L2J_Mobius_4.0_GrandCrusade/java/org/l2jmobius/gameserver/communitybbs/BB/Forum.java

@@ -19,10 +19,9 @@ package org.l2jmobius.gameserver.communitybbs.BB;
 import java.sql.Connection;
 import java.sql.PreparedStatement;
 import java.sql.ResultSet;
-import java.util.List;
+import java.util.Collection;
 import java.util.Map;
 import java.util.concurrent.ConcurrentHashMap;
-import java.util.concurrent.CopyOnWriteArrayList;
 import java.util.logging.Level;
 import java.util.logging.Logger;
 
@@ -46,7 +45,7 @@ public class Forum
 	public static final int CLANMEMBERONLY = 2;
 	public static final int OWNERONLY = 3;
 	
-	private final List<Forum> _children;
+	private final Collection<Forum> _children;
 	private final Map<Integer, Topic> _topic = new ConcurrentHashMap<>();
 	private final int _forumId;
 	private String _forumName;
@@ -66,7 +65,7 @@ public class Forum
 	{
 		_forumId = Forumid;
 		_fParent = FParent;
-		_children = new CopyOnWriteArrayList<>();
+		_children = ConcurrentHashMap.newKeySet();
 	}
 	
 	/**
@@ -85,7 +84,7 @@ public class Forum
 		_forumPerm = perm;
 		_fParent = parent;
 		_ownerID = OwnerID;
-		_children = new CopyOnWriteArrayList<>();
+		_children = ConcurrentHashMap.newKeySet();
 		parent._children.add(this);
 		ForumsBBSManager.getInstance().addForum(this);
 		_loaded = true;

L2J_Mobius_4.0_GrandCrusade/java/org/l2jmobius/gameserver/communitybbs/BB/Post.java

@@ -19,8 +19,8 @@ package org.l2jmobius.gameserver.communitybbs.BB;
 import java.sql.Connection;
 import java.sql.PreparedStatement;
 import java.sql.ResultSet;
-import java.util.List;
+import java.util.Collection;
-import java.util.concurrent.CopyOnWriteArrayList;
+import java.util.concurrent.ConcurrentHashMap;
 import java.util.logging.Level;
 import java.util.logging.Logger;
 
@@ -45,7 +45,7 @@ public class Post
 		public String postTxt;
 	}
 	
-	private final List<CPost> _post;
+	private final Collection<CPost> _post;
 	
 	/**
 	 * @param _PostOwner
@@ -57,7 +57,7 @@ public class Post
 	 */
 	public Post(String _PostOwner, int _PostOwnerID, long date, int tid, int _PostForumID, String txt)
 	{
-		_post = new CopyOnWriteArrayList<>();
+		_post = ConcurrentHashMap.newKeySet();
 		final CPost cp = new CPost();
 		cp.postId = 0;
 		cp.postOwner = _PostOwner;
@@ -92,7 +92,7 @@ public class Post
 	
 	public Post(Topic t)
 	{
-		_post = new CopyOnWriteArrayList<>();
+		_post = ConcurrentHashMap.newKeySet();
 		load(t);
 	}
 	

L2J_Mobius_4.0_GrandCrusade/java/org/l2jmobius/gameserver/communitybbs/Manager/ForumsBBSManager.java

@@ -19,8 +19,8 @@ package org.l2jmobius.gameserver.communitybbs.Manager;
 import java.sql.Connection;
 import java.sql.ResultSet;
 import java.sql.Statement;
-import java.util.List;
+import java.util.Collection;
-import java.util.concurrent.CopyOnWriteArrayList;
+import java.util.concurrent.ConcurrentHashMap;
 import java.util.logging.Level;
 import java.util.logging.Logger;
 
@@ -31,7 +31,7 @@ import org.l2jmobius.gameserver.model.actor.instance.PlayerInstance;
 public class ForumsBBSManager extends BaseBBSManager
 {
 	private static Logger LOGGER = Logger.getLogger(ForumsBBSManager.class.getName());
-	private final List<Forum> _table;
+	private final Collection<Forum> _table;
 	private int _lastid = 1;
 	
 	/**
@@ -39,7 +39,7 @@ public class ForumsBBSManager extends BaseBBSManager
 	 */
 	protected ForumsBBSManager()
 	{
-		_table = new CopyOnWriteArrayList<>();
+		_table = ConcurrentHashMap.newKeySet();
 		try (Connection con = DatabaseFactory.getConnection();
 			Statement s = con.createStatement();
 			ResultSet rs = s.executeQuery("SELECT forum_id FROM forums WHERE forum_type = 0"))

L2J_Mobius_4.0_GrandCrusade/java/org/l2jmobius/gameserver/communitybbs/Manager/TopicBBSManager.java

@@ -18,12 +18,11 @@ package org.l2jmobius.gameserver.communitybbs.Manager;
 
 import java.text.DateFormat;
 import java.util.Calendar;
+import java.util.Collection;
 import java.util.Date;
-import java.util.List;
 import java.util.Map;
 import java.util.StringTokenizer;
 import java.util.concurrent.ConcurrentHashMap;
-import java.util.concurrent.CopyOnWriteArrayList;
 
 import org.l2jmobius.gameserver.communitybbs.BB.Forum;
 import org.l2jmobius.gameserver.communitybbs.BB.Post;
@@ -34,7 +33,7 @@ import org.l2jmobius.gameserver.model.actor.instance.PlayerInstance;
 
 public class TopicBBSManager extends BaseBBSManager
 {
-	private final List<Topic> _table = new CopyOnWriteArrayList<>();
+	private final Collection<Topic> _table = ConcurrentHashMap.newKeySet();
 	private final Map<Forum, Integer> _maxId = new ConcurrentHashMap<>();
 	
 	protected TopicBBSManager()

L2J_Mobius_4.0_GrandCrusade/java/org/l2jmobius/gameserver/data/xml/impl/NpcData.java

@@ -18,6 +18,7 @@ package org.l2jmobius.gameserver.data.xml.impl;
 
 import java.io.File;
 import java.util.ArrayList;
+import java.util.Collection;
 import java.util.Collections;
 import java.util.EnumMap;
 import java.util.HashMap;
@@ -27,7 +28,6 @@ import java.util.Map;
 import java.util.Map.Entry;
 import java.util.Set;
 import java.util.concurrent.ConcurrentHashMap;
-import java.util.concurrent.CopyOnWriteArrayList;
 import java.util.function.Predicate;
 import java.util.logging.Logger;
 import java.util.stream.Collectors;
@@ -60,7 +60,7 @@ public class NpcData implements IXmlReader
 	
 	private final Map<Integer, NpcTemplate> _npcs = new ConcurrentHashMap<>();
 	private final Map<String, Integer> _clans = new ConcurrentHashMap<>();
-	private static final List<Integer> _masterMonsterIDs = new CopyOnWriteArrayList<>();
+	private static final Collection<Integer> _masterMonsterIDs = ConcurrentHashMap.newKeySet();
 	
 	protected NpcData()
 	{
@@ -789,7 +789,7 @@ public class NpcData implements IXmlReader
 	/**
 	 * @return the IDs of monsters that have minions.
 	 */
-	public static List<Integer> getMasterMonsterIDs()
+	public static Collection<Integer> getMasterMonsterIDs()
 	{
 		return _masterMonsterIDs;
 	}

L2J_Mobius_4.0_GrandCrusade/java/org/l2jmobius/gameserver/data/xml/impl/SpawnsData.java

@@ -18,10 +18,11 @@ package org.l2jmobius.gameserver.data.xml.impl;
 
 import java.io.File;
 import java.util.ArrayList;
+import java.util.Collection;
 import java.util.Collections;
 import java.util.List;
 import java.util.Map;
-import java.util.concurrent.CopyOnWriteArrayList;
+import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.ScheduledFuture;
 import java.util.function.Predicate;
 import java.util.logging.Level;
@@ -54,7 +55,7 @@ public class SpawnsData implements IXmlReader
 {
 	protected static final Logger LOGGER = Logger.getLogger(SpawnsData.class.getName());
 	
-	private final List<SpawnTemplate> _spawns = new CopyOnWriteArrayList<>();
+	private final Collection<SpawnTemplate> _spawns = ConcurrentHashMap.newKeySet();
 	
 	protected SpawnsData()
 	{
@@ -98,7 +99,7 @@ public class SpawnsData implements IXmlReader
 		
 		if (Config.THREADS_FOR_LOADING)
 		{
-			final List<ScheduledFuture<?>> jobs = new CopyOnWriteArrayList<>();
+			final Collection<ScheduledFuture<?>> jobs = ConcurrentHashMap.newKeySet();
 			for (SpawnTemplate template : _spawns)
 			{
 				if (template.isSpawningByDefault())
@@ -146,7 +147,7 @@ public class SpawnsData implements IXmlReader
 		LOGGER.info(getClass().getSimpleName() + ": All spawns has been removed!");
 	}
 	
-	public List<SpawnTemplate> getSpawns()
+	public Collection<SpawnTemplate> getSpawns()
 	{
 		return _spawns;
 	}
@@ -166,7 +167,7 @@ public class SpawnsData implements IXmlReader
 		return _spawns.stream().flatMap(template -> template.getGroups().stream()).flatMap(group -> group.getSpawns().stream()).filter(condition).collect(Collectors.toList());
 	}
 	
-	public void parseSpawn(Node spawnsNode, File file, List<SpawnTemplate> spawns)
+	public void parseSpawn(Node spawnsNode, File file, Collection<SpawnTemplate> spawns)
 	{
 		final SpawnTemplate spawnTemplate = new SpawnTemplate(new StatsSet(parseAttributes(spawnsNode)), file);
 		SpawnGroup defaultGroup = null;

L2J_Mobius_4.0_GrandCrusade/java/org/l2jmobius/gameserver/datatables/EventDroplist.java

@@ -16,10 +16,11 @@
  */
 package org.l2jmobius.gameserver.datatables;
 
+import java.util.Collection;
 import java.util.Date;
 import java.util.LinkedList;
 import java.util.List;
-import java.util.concurrent.CopyOnWriteArrayList;
+import java.util.concurrent.ConcurrentHashMap;
 
 import org.l2jmobius.gameserver.script.DateRange;
 import org.l2jmobius.gameserver.script.EventDrop;
@@ -35,7 +36,7 @@ public class EventDroplist
 	/**
 	 * The table containing all DataDrop object
 	 */
-	private static final List<DateDrop> ALL_NPC_DATE_DROPS = new CopyOnWriteArrayList<>();
+	private static final Collection<DateDrop> ALL_NPC_DATE_DROPS = ConcurrentHashMap.newKeySet();
 	
 	public static class DateDrop
 	{

L2J_Mobius_4.0_GrandCrusade/java/org/l2jmobius/gameserver/engines/DocumentEngine.java

@@ -18,8 +18,9 @@ package org.l2jmobius.gameserver.engines;
 
 import java.io.File;
 import java.util.ArrayList;
+import java.util.Collection;
 import java.util.List;
-import java.util.concurrent.CopyOnWriteArrayList;
+import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.ScheduledFuture;
 import java.util.logging.Logger;
 
@@ -66,13 +67,13 @@ public class DocumentEngine
 	 * Return created items
 	 * @return List of {@link Item}
 	 */
-	public List<Item> loadItems()
+	public Collection<Item> loadItems()
 	{
-		final List<Item> list = new CopyOnWriteArrayList<>();
+		final Collection<Item> list = ConcurrentHashMap.newKeySet();
 		
 		if (Config.THREADS_FOR_LOADING)
 		{
-			final List<ScheduledFuture<?>> jobs = new CopyOnWriteArrayList<>();
+			final Collection<ScheduledFuture<?>> jobs = ConcurrentHashMap.newKeySet();
 			for (File file : _itemFiles)
 			{
 				jobs.add(ThreadPool.schedule(() ->

L2J_Mobius_4.0_GrandCrusade/java/org/l2jmobius/gameserver/model/CommandChannel.java

@@ -16,9 +16,10 @@
  */
 package org.l2jmobius.gameserver.model;
 
+import java.util.Collection;
 import java.util.LinkedList;
 import java.util.List;
-import java.util.concurrent.CopyOnWriteArrayList;
+import java.util.concurrent.ConcurrentHashMap;
 import java.util.function.Function;
 
 import org.l2jmobius.Config;
@@ -36,7 +37,7 @@ import org.l2jmobius.gameserver.network.serverpackets.SystemMessage;
  */
 public class CommandChannel extends AbstractPlayerGroup
 {
-	private final List<Party> _parties = new CopyOnWriteArrayList<>();
+	private final Collection<Party> _parties = ConcurrentHashMap.newKeySet();
 	private PlayerInstance _commandLeader;
 	private int _channelLvl;
 	
@@ -150,7 +151,7 @@ public class CommandChannel extends AbstractPlayerGroup
 	/**
 	 * @return a list of all parties in this command channel
 	 */
-	public List<Party> getPartys()
+	public Collection<Party> getParties()
 	{
 		return _parties;
 	}

L2J_Mobius_4.0_GrandCrusade/java/org/l2jmobius/gameserver/model/Petition.java

@@ -16,8 +16,8 @@
  */
 package org.l2jmobius.gameserver.model;
 
-import java.util.List;
+import java.util.Collection;
-import java.util.concurrent.CopyOnWriteArrayList;
+import java.util.concurrent.ConcurrentHashMap;
 
 import org.l2jmobius.gameserver.enums.PetitionState;
 import org.l2jmobius.gameserver.enums.PetitionType;
@@ -41,7 +41,7 @@ public class Petition
 	private final PetitionType _type;
 	private PetitionState _state = PetitionState.PENDING;
 	private final String _content;
-	private final List<CreatureSay> _messageLog = new CopyOnWriteArrayList<>();
+	private final Collection<CreatureSay> _messageLog = ConcurrentHashMap.newKeySet();
 	private final PlayerInstance _petitioner;
 	private PlayerInstance _responder;
 	
@@ -58,7 +58,7 @@ public class Petition
 		return _messageLog.add(cs);
 	}
 	
-	public List<CreatureSay> getLogMessages()
+	public Collection<CreatureSay> getLogMessages()
 	{
 		return _messageLog;
 	}

L2J_Mobius_4.0_GrandCrusade/java/org/l2jmobius/gameserver/model/actor/instance/RaceManagerInstance.java

@@ -16,8 +16,8 @@
  */
 package org.l2jmobius.gameserver.model.actor.instance;
 
-import java.util.List;
+import java.util.Collection;
-import java.util.concurrent.CopyOnWriteArrayList;
+import java.util.concurrent.ConcurrentHashMap;
 
 import org.l2jmobius.Config;
 import org.l2jmobius.commons.concurrent.ThreadPool;
@@ -45,7 +45,7 @@ public class RaceManagerInstance extends Npc
 	public static final int LANES = 8;
 	public static final int WINDOW_START = 0;
 	
-	private static List<RaceManagerInstance> _managers;
+	private static Collection<RaceManagerInstance> _managers;
 	protected static int _raceNumber = 4;
 	
 	// Time Constants
@@ -104,7 +104,7 @@ public class RaceManagerInstance extends Npc
 		{
 			_notInitialized = false;
 			
-			_managers = new CopyOnWriteArrayList<>();
+			_managers = ConcurrentHashMap.newKeySet();
 			
 			ThreadPool.scheduleAtFixedRate(new Announcement(SystemMessageId.TICKETS_ARE_NOW_AVAILABLE_FOR_MONSTER_RACE_S1), 0, 10 * MINUTE);
 			ThreadPool.scheduleAtFixedRate(new Announcement(SystemMessageId.NOW_SELLING_TICKETS_FOR_MONSTER_RACE_S1), 30 * SECOND, 10 * MINUTE);

L2J_Mobius_4.0_GrandCrusade/java/org/l2jmobius/gameserver/model/actor/instance/ServitorInstance.java

@@ -19,10 +19,12 @@ package org.l2jmobius.gameserver.model.actor.instance;
 import java.sql.Connection;
 import java.sql.PreparedStatement;
 import java.sql.ResultSet;
+import java.util.Collection;
 import java.util.Collections;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.CopyOnWriteArrayList;
 import java.util.concurrent.Future;
 import java.util.logging.Level;
@@ -304,7 +306,7 @@ public class ServitorInstance extends Summon implements Runnable
 			
 			int buff_index = 0;
 			
-			final List<Long> storedSkills = new CopyOnWriteArrayList<>();
+			final Collection<Long> storedSkills = ConcurrentHashMap.newKeySet();
 			
 			// Store all effect data along with calculated remaining
 			if (storeEffects)

L2J_Mobius_4.0_GrandCrusade/java/org/l2jmobius/gameserver/model/actor/instance/TamedBeastInstance.java

@@ -18,8 +18,8 @@ package org.l2jmobius.gameserver.model.actor.instance;
 
 import static org.l2jmobius.gameserver.ai.CtrlIntention.AI_INTENTION_IDLE;
 
-import java.util.List;
+import java.util.Collection;
-import java.util.concurrent.CopyOnWriteArrayList;
+import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.Future;
 
 import org.l2jmobius.commons.concurrent.ThreadPool;
@@ -62,7 +62,7 @@ public class TamedBeastInstance extends FeedableBeastInstance
 	private Future<?> _buffTask = null;
 	private Future<?> _durationCheckTask = null;
 	protected boolean _isFreyaBeast;
-	private List<Skill> _beastSkills = null;
+	private Collection<Skill> _beastSkills = null;
 	
 	public TamedBeastInstance(int npcTemplateId)
 	{
@@ -205,7 +205,7 @@ public class TamedBeastInstance extends FeedableBeastInstance
 	{
 		if (_beastSkills == null)
 		{
-			_beastSkills = new CopyOnWriteArrayList<>();
+			_beastSkills = ConcurrentHashMap.newKeySet();
 		}
 		_beastSkills.add(skill);
 	}

L2J_Mobius_4.0_GrandCrusade/java/org/l2jmobius/gameserver/model/entity/Siegable.java

@@ -49,7 +49,7 @@ public interface Siegable
 	
 	SiegeClan getDefenderClan(Clan clan);
 	
-	List<SiegeClan> getDefenderClans();
+	Collection<SiegeClan> getDefenderClans();
 	
 	boolean checkIsDefender(Clan clan);
 	

L2J_Mobius_4.0_GrandCrusade/java/org/l2jmobius/gameserver/model/entity/Siege.java

@@ -21,12 +21,13 @@ import java.sql.PreparedStatement;
 import java.sql.ResultSet;
 import java.util.ArrayList;
 import java.util.Calendar;
+import java.util.Collection;
 import java.util.Collections;
 import java.util.Iterator;
 import java.util.List;
 import java.util.Objects;
 import java.util.Set;
-import java.util.concurrent.CopyOnWriteArrayList;
+import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.ScheduledFuture;
 import java.util.logging.Level;
 import java.util.logging.Logger;
@@ -221,9 +222,9 @@ public class Siege implements Siegable
 	}
 	
 	// must support Concurrent Modifications
-	private final List<SiegeClan> _attackerClans = new CopyOnWriteArrayList<>();
+	private final Collection<SiegeClan> _attackerClans = ConcurrentHashMap.newKeySet();
-	private final List<SiegeClan> _defenderClans = new CopyOnWriteArrayList<>();
+	private final Collection<SiegeClan> _defenderClans = ConcurrentHashMap.newKeySet();
-	private final List<SiegeClan> _defenderWaitingClans = new CopyOnWriteArrayList<>();
+	private final Collection<SiegeClan> _defenderWaitingClans = ConcurrentHashMap.newKeySet();
 	
 	// Castle setting
 	private final List<ControlTowerInstance> _controlTowers = new ArrayList<>();
@@ -1582,7 +1583,7 @@ public class Siege implements Siegable
 	}
 	
 	@Override
-	public List<SiegeClan> getAttackerClans()
+	public Collection<SiegeClan> getAttackerClans()
 	{
 		if (_isNormalSide)
 		{
@@ -1625,7 +1626,7 @@ public class Siege implements Siegable
 	}
 	
 	@Override
-	public List<SiegeClan> getDefenderClans()
+	public Collection<SiegeClan> getDefenderClans()
 	{
 		if (_isNormalSide)
 		{
@@ -1655,7 +1656,7 @@ public class Siege implements Siegable
 		return null;
 	}
 	
-	public List<SiegeClan> getDefenderWaitingClans()
+	public Collection<SiegeClan> getDefenderWaitingClans()
 	{
 		return _defenderWaitingClans;
 	}

L2J_Mobius_4.0_GrandCrusade/java/org/l2jmobius/gameserver/model/holders/MovieHolder.java

@@ -16,8 +16,9 @@
  */
 package org.l2jmobius.gameserver.model.holders;
 
+import java.util.Collection;
 import java.util.List;
-import java.util.concurrent.CopyOnWriteArrayList;
+import java.util.concurrent.ConcurrentHashMap;
 
 import org.l2jmobius.gameserver.enums.Movie;
 import org.l2jmobius.gameserver.model.actor.instance.PlayerInstance;
@@ -29,7 +30,7 @@ public class MovieHolder
 {
 	private final Movie _movie;
 	private final List<PlayerInstance> _players;
-	private final List<PlayerInstance> _votedPlayers = new CopyOnWriteArrayList<>();
+	private final Collection<PlayerInstance> _votedPlayers = ConcurrentHashMap.newKeySet();
 	
 	public MovieHolder(List<PlayerInstance> players, Movie movie)
 	{
@@ -64,7 +65,7 @@ public class MovieHolder
 		return _players;
 	}
 	
-	public List<PlayerInstance> getVotedPlayers()
+	public Collection<PlayerInstance> getVotedPlayers()
 	{
 		return _votedPlayers;
 	}