diff --git a/L2J_Mobius_01.0_Ertheia/java/org/l2jmobius/gameserver/network/serverpackets/ExAcquireSkillInfo.java b/L2J_Mobius_01.0_Ertheia/java/org/l2jmobius/gameserver/network/serverpackets/ExAcquireSkillInfo.java
index a1ff065846..9a1d5beb11 100644
--- a/L2J_Mobius_01.0_Ertheia/java/org/l2jmobius/gameserver/network/serverpackets/ExAcquireSkillInfo.java
+++ b/L2J_Mobius_01.0_Ertheia/java/org/l2jmobius/gameserver/network/serverpackets/ExAcquireSkillInfo.java
@@ -16,10 +16,9 @@
  */
 package org.l2jmobius.gameserver.network.serverpackets;
 
+import java.util.LinkedList;
 import java.util.List;
-import java.util.Objects;
 import java.util.Set;
-import java.util.stream.Collectors;
 
 import org.l2jmobius.gameserver.model.SkillLearn;
 import org.l2jmobius.gameserver.model.actor.Player;
@@ -38,7 +37,7 @@ public class ExAcquireSkillInfo extends ServerPacket
 	private final long _spCost;
 	private final int _minLevel;
 	private final Set<ItemHolder> _itemReq;
-	private final List<Skill> _skillRem;
+	private final List<Skill> _skillRem = new LinkedList<>();
 	
 	/**
 	 * Special constructor for Alternate Skill Learning system.<br>
@@ -54,7 +53,14 @@ public class ExAcquireSkillInfo extends ServerPacket
 		_spCost = skillLearn.getLevelUpSp();
 		_minLevel = skillLearn.getGetLevel();
 		_itemReq = skillLearn.getRequiredItems();
-		_skillRem = skillLearn.getRemoveSkills().stream().map(player::getKnownSkill).filter(Objects::nonNull).collect(Collectors.toList());
+		for (int id : skillLearn.getRemoveSkills())
+		{
+			final Skill removeSkill = player.getKnownSkill(id);
+			if (removeSkill != null)
+			{
+				_skillRem.add(removeSkill);
+			}
+		}
 	}
 	
 	@Override
diff --git a/L2J_Mobius_02.5_Underground/java/org/l2jmobius/gameserver/network/serverpackets/ExAcquireSkillInfo.java b/L2J_Mobius_02.5_Underground/java/org/l2jmobius/gameserver/network/serverpackets/ExAcquireSkillInfo.java
index a1ff065846..9a1d5beb11 100644
--- a/L2J_Mobius_02.5_Underground/java/org/l2jmobius/gameserver/network/serverpackets/ExAcquireSkillInfo.java
+++ b/L2J_Mobius_02.5_Underground/java/org/l2jmobius/gameserver/network/serverpackets/ExAcquireSkillInfo.java
@@ -16,10 +16,9 @@
  */
 package org.l2jmobius.gameserver.network.serverpackets;
 
+import java.util.LinkedList;
 import java.util.List;
-import java.util.Objects;
 import java.util.Set;
-import java.util.stream.Collectors;
 
 import org.l2jmobius.gameserver.model.SkillLearn;
 import org.l2jmobius.gameserver.model.actor.Player;
@@ -38,7 +37,7 @@ public class ExAcquireSkillInfo extends ServerPacket
 	private final long _spCost;
 	private final int _minLevel;
 	private final Set<ItemHolder> _itemReq;
-	private final List<Skill> _skillRem;
+	private final List<Skill> _skillRem = new LinkedList<>();
 	
 	/**
 	 * Special constructor for Alternate Skill Learning system.<br>
@@ -54,7 +53,14 @@ public class ExAcquireSkillInfo extends ServerPacket
 		_spCost = skillLearn.getLevelUpSp();
 		_minLevel = skillLearn.getGetLevel();
 		_itemReq = skillLearn.getRequiredItems();
-		_skillRem = skillLearn.getRemoveSkills().stream().map(player::getKnownSkill).filter(Objects::nonNull).collect(Collectors.toList());
+		for (int id : skillLearn.getRemoveSkills())
+		{
+			final Skill removeSkill = player.getKnownSkill(id);
+			if (removeSkill != null)
+			{
+				_skillRem.add(removeSkill);
+			}
+		}
 	}
 	
 	@Override
diff --git a/L2J_Mobius_03.0_Helios/java/org/l2jmobius/gameserver/network/serverpackets/ExAcquireSkillInfo.java b/L2J_Mobius_03.0_Helios/java/org/l2jmobius/gameserver/network/serverpackets/ExAcquireSkillInfo.java
index a1ff065846..9a1d5beb11 100644
--- a/L2J_Mobius_03.0_Helios/java/org/l2jmobius/gameserver/network/serverpackets/ExAcquireSkillInfo.java
+++ b/L2J_Mobius_03.0_Helios/java/org/l2jmobius/gameserver/network/serverpackets/ExAcquireSkillInfo.java
@@ -16,10 +16,9 @@
  */
 package org.l2jmobius.gameserver.network.serverpackets;
 
+import java.util.LinkedList;
 import java.util.List;
-import java.util.Objects;
 import java.util.Set;
-import java.util.stream.Collectors;
 
 import org.l2jmobius.gameserver.model.SkillLearn;
 import org.l2jmobius.gameserver.model.actor.Player;
@@ -38,7 +37,7 @@ public class ExAcquireSkillInfo extends ServerPacket
 	private final long _spCost;
 	private final int _minLevel;
 	private final Set<ItemHolder> _itemReq;
-	private final List<Skill> _skillRem;
+	private final List<Skill> _skillRem = new LinkedList<>();
 	
 	/**
 	 * Special constructor for Alternate Skill Learning system.<br>
@@ -54,7 +53,14 @@ public class ExAcquireSkillInfo extends ServerPacket
 		_spCost = skillLearn.getLevelUpSp();
 		_minLevel = skillLearn.getGetLevel();
 		_itemReq = skillLearn.getRequiredItems();
-		_skillRem = skillLearn.getRemoveSkills().stream().map(player::getKnownSkill).filter(Objects::nonNull).collect(Collectors.toList());
+		for (int id : skillLearn.getRemoveSkills())
+		{
+			final Skill removeSkill = player.getKnownSkill(id);
+			if (removeSkill != null)
+			{
+				_skillRem.add(removeSkill);
+			}
+		}
 	}
 	
 	@Override
diff --git a/L2J_Mobius_04.0_GrandCrusade/java/org/l2jmobius/gameserver/network/serverpackets/ExAcquireSkillInfo.java b/L2J_Mobius_04.0_GrandCrusade/java/org/l2jmobius/gameserver/network/serverpackets/ExAcquireSkillInfo.java
index a1ff065846..9a1d5beb11 100644
--- a/L2J_Mobius_04.0_GrandCrusade/java/org/l2jmobius/gameserver/network/serverpackets/ExAcquireSkillInfo.java
+++ b/L2J_Mobius_04.0_GrandCrusade/java/org/l2jmobius/gameserver/network/serverpackets/ExAcquireSkillInfo.java
@@ -16,10 +16,9 @@
  */
 package org.l2jmobius.gameserver.network.serverpackets;
 
+import java.util.LinkedList;
 import java.util.List;
-import java.util.Objects;
 import java.util.Set;
-import java.util.stream.Collectors;
 
 import org.l2jmobius.gameserver.model.SkillLearn;
 import org.l2jmobius.gameserver.model.actor.Player;
@@ -38,7 +37,7 @@ public class ExAcquireSkillInfo extends ServerPacket
 	private final long _spCost;
 	private final int _minLevel;
 	private final Set<ItemHolder> _itemReq;
-	private final List<Skill> _skillRem;
+	private final List<Skill> _skillRem = new LinkedList<>();
 	
 	/**
 	 * Special constructor for Alternate Skill Learning system.<br>
@@ -54,7 +53,14 @@ public class ExAcquireSkillInfo extends ServerPacket
 		_spCost = skillLearn.getLevelUpSp();
 		_minLevel = skillLearn.getGetLevel();
 		_itemReq = skillLearn.getRequiredItems();
-		_skillRem = skillLearn.getRemoveSkills().stream().map(player::getKnownSkill).filter(Objects::nonNull).collect(Collectors.toList());
+		for (int id : skillLearn.getRemoveSkills())
+		{
+			final Skill removeSkill = player.getKnownSkill(id);
+			if (removeSkill != null)
+			{
+				_skillRem.add(removeSkill);
+			}
+		}
 	}
 	
 	@Override
diff --git a/L2J_Mobius_05.0_Salvation/java/org/l2jmobius/gameserver/network/serverpackets/ExAcquireSkillInfo.java b/L2J_Mobius_05.0_Salvation/java/org/l2jmobius/gameserver/network/serverpackets/ExAcquireSkillInfo.java
index a1ff065846..9a1d5beb11 100644
--- a/L2J_Mobius_05.0_Salvation/java/org/l2jmobius/gameserver/network/serverpackets/ExAcquireSkillInfo.java
+++ b/L2J_Mobius_05.0_Salvation/java/org/l2jmobius/gameserver/network/serverpackets/ExAcquireSkillInfo.java
@@ -16,10 +16,9 @@
  */
 package org.l2jmobius.gameserver.network.serverpackets;
 
+import java.util.LinkedList;
 import java.util.List;
-import java.util.Objects;
 import java.util.Set;
-import java.util.stream.Collectors;
 
 import org.l2jmobius.gameserver.model.SkillLearn;
 import org.l2jmobius.gameserver.model.actor.Player;
@@ -38,7 +37,7 @@ public class ExAcquireSkillInfo extends ServerPacket
 	private final long _spCost;
 	private final int _minLevel;
 	private final Set<ItemHolder> _itemReq;
-	private final List<Skill> _skillRem;
+	private final List<Skill> _skillRem = new LinkedList<>();
 	
 	/**
 	 * Special constructor for Alternate Skill Learning system.<br>
@@ -54,7 +53,14 @@ public class ExAcquireSkillInfo extends ServerPacket
 		_spCost = skillLearn.getLevelUpSp();
 		_minLevel = skillLearn.getGetLevel();
 		_itemReq = skillLearn.getRequiredItems();
-		_skillRem = skillLearn.getRemoveSkills().stream().map(player::getKnownSkill).filter(Objects::nonNull).collect(Collectors.toList());
+		for (int id : skillLearn.getRemoveSkills())
+		{
+			final Skill removeSkill = player.getKnownSkill(id);
+			if (removeSkill != null)
+			{
+				_skillRem.add(removeSkill);
+			}
+		}
 	}
 	
 	@Override
diff --git a/L2J_Mobius_05.5_EtinasFate/java/org/l2jmobius/gameserver/network/serverpackets/ExAcquireSkillInfo.java b/L2J_Mobius_05.5_EtinasFate/java/org/l2jmobius/gameserver/network/serverpackets/ExAcquireSkillInfo.java
index a1ff065846..9a1d5beb11 100644
--- a/L2J_Mobius_05.5_EtinasFate/java/org/l2jmobius/gameserver/network/serverpackets/ExAcquireSkillInfo.java
+++ b/L2J_Mobius_05.5_EtinasFate/java/org/l2jmobius/gameserver/network/serverpackets/ExAcquireSkillInfo.java
@@ -16,10 +16,9 @@
  */
 package org.l2jmobius.gameserver.network.serverpackets;
 
+import java.util.LinkedList;
 import java.util.List;
-import java.util.Objects;
 import java.util.Set;
-import java.util.stream.Collectors;
 
 import org.l2jmobius.gameserver.model.SkillLearn;
 import org.l2jmobius.gameserver.model.actor.Player;
@@ -38,7 +37,7 @@ public class ExAcquireSkillInfo extends ServerPacket
 	private final long _spCost;
 	private final int _minLevel;
 	private final Set<ItemHolder> _itemReq;
-	private final List<Skill> _skillRem;
+	private final List<Skill> _skillRem = new LinkedList<>();
 	
 	/**
 	 * Special constructor for Alternate Skill Learning system.<br>
@@ -54,7 +53,14 @@ public class ExAcquireSkillInfo extends ServerPacket
 		_spCost = skillLearn.getLevelUpSp();
 		_minLevel = skillLearn.getGetLevel();
 		_itemReq = skillLearn.getRequiredItems();
-		_skillRem = skillLearn.getRemoveSkills().stream().map(player::getKnownSkill).filter(Objects::nonNull).collect(Collectors.toList());
+		for (int id : skillLearn.getRemoveSkills())
+		{
+			final Skill removeSkill = player.getKnownSkill(id);
+			if (removeSkill != null)
+			{
+				_skillRem.add(removeSkill);
+			}
+		}
 	}
 	
 	@Override
diff --git a/L2J_Mobius_06.0_Fafurion/java/org/l2jmobius/gameserver/network/serverpackets/ExAcquireSkillInfo.java b/L2J_Mobius_06.0_Fafurion/java/org/l2jmobius/gameserver/network/serverpackets/ExAcquireSkillInfo.java
index a1ff065846..9a1d5beb11 100644
--- a/L2J_Mobius_06.0_Fafurion/java/org/l2jmobius/gameserver/network/serverpackets/ExAcquireSkillInfo.java
+++ b/L2J_Mobius_06.0_Fafurion/java/org/l2jmobius/gameserver/network/serverpackets/ExAcquireSkillInfo.java
@@ -16,10 +16,9 @@
  */
 package org.l2jmobius.gameserver.network.serverpackets;
 
+import java.util.LinkedList;
 import java.util.List;
-import java.util.Objects;
 import java.util.Set;
-import java.util.stream.Collectors;
 
 import org.l2jmobius.gameserver.model.SkillLearn;
 import org.l2jmobius.gameserver.model.actor.Player;
@@ -38,7 +37,7 @@ public class ExAcquireSkillInfo extends ServerPacket
 	private final long _spCost;
 	private final int _minLevel;
 	private final Set<ItemHolder> _itemReq;
-	private final List<Skill> _skillRem;
+	private final List<Skill> _skillRem = new LinkedList<>();
 	
 	/**
 	 * Special constructor for Alternate Skill Learning system.<br>
@@ -54,7 +53,14 @@ public class ExAcquireSkillInfo extends ServerPacket
 		_spCost = skillLearn.getLevelUpSp();
 		_minLevel = skillLearn.getGetLevel();
 		_itemReq = skillLearn.getRequiredItems();
-		_skillRem = skillLearn.getRemoveSkills().stream().map(player::getKnownSkill).filter(Objects::nonNull).collect(Collectors.toList());
+		for (int id : skillLearn.getRemoveSkills())
+		{
+			final Skill removeSkill = player.getKnownSkill(id);
+			if (removeSkill != null)
+			{
+				_skillRem.add(removeSkill);
+			}
+		}
 	}
 	
 	@Override
diff --git a/L2J_Mobius_07.0_PreludeOfWar/java/org/l2jmobius/gameserver/network/serverpackets/ExAcquireSkillInfo.java b/L2J_Mobius_07.0_PreludeOfWar/java/org/l2jmobius/gameserver/network/serverpackets/ExAcquireSkillInfo.java
index a1ff065846..9a1d5beb11 100644
--- a/L2J_Mobius_07.0_PreludeOfWar/java/org/l2jmobius/gameserver/network/serverpackets/ExAcquireSkillInfo.java
+++ b/L2J_Mobius_07.0_PreludeOfWar/java/org/l2jmobius/gameserver/network/serverpackets/ExAcquireSkillInfo.java
@@ -16,10 +16,9 @@
  */
 package org.l2jmobius.gameserver.network.serverpackets;
 
+import java.util.LinkedList;
 import java.util.List;
-import java.util.Objects;
 import java.util.Set;
-import java.util.stream.Collectors;
 
 import org.l2jmobius.gameserver.model.SkillLearn;
 import org.l2jmobius.gameserver.model.actor.Player;
@@ -38,7 +37,7 @@ public class ExAcquireSkillInfo extends ServerPacket
 	private final long _spCost;
 	private final int _minLevel;
 	private final Set<ItemHolder> _itemReq;
-	private final List<Skill> _skillRem;
+	private final List<Skill> _skillRem = new LinkedList<>();
 	
 	/**
 	 * Special constructor for Alternate Skill Learning system.<br>
@@ -54,7 +53,14 @@ public class ExAcquireSkillInfo extends ServerPacket
 		_spCost = skillLearn.getLevelUpSp();
 		_minLevel = skillLearn.getGetLevel();
 		_itemReq = skillLearn.getRequiredItems();
-		_skillRem = skillLearn.getRemoveSkills().stream().map(player::getKnownSkill).filter(Objects::nonNull).collect(Collectors.toList());
+		for (int id : skillLearn.getRemoveSkills())
+		{
+			final Skill removeSkill = player.getKnownSkill(id);
+			if (removeSkill != null)
+			{
+				_skillRem.add(removeSkill);
+			}
+		}
 	}
 	
 	@Override
diff --git a/L2J_Mobius_08.2_Homunculus/java/org/l2jmobius/gameserver/network/serverpackets/ExAcquireSkillInfo.java b/L2J_Mobius_08.2_Homunculus/java/org/l2jmobius/gameserver/network/serverpackets/ExAcquireSkillInfo.java
index 9df735739f..67d8840e92 100644
--- a/L2J_Mobius_08.2_Homunculus/java/org/l2jmobius/gameserver/network/serverpackets/ExAcquireSkillInfo.java
+++ b/L2J_Mobius_08.2_Homunculus/java/org/l2jmobius/gameserver/network/serverpackets/ExAcquireSkillInfo.java
@@ -16,9 +16,8 @@
  */
 package org.l2jmobius.gameserver.network.serverpackets;
 
+import java.util.LinkedList;
 import java.util.List;
-import java.util.Objects;
-import java.util.stream.Collectors;
 
 import org.l2jmobius.gameserver.model.SkillLearn;
 import org.l2jmobius.gameserver.model.actor.Player;
@@ -37,7 +36,7 @@ public class ExAcquireSkillInfo extends ServerPacket
 	private final long _spCost;
 	private final int _minLevel;
 	private final List<List<ItemHolder>> _itemReq;
-	private final List<Skill> _skillRem;
+	private final List<Skill> _skillRem = new LinkedList<>();
 	
 	/**
 	 * Special constructor for Alternate Skill Learning system.<br>
@@ -53,7 +52,14 @@ public class ExAcquireSkillInfo extends ServerPacket
 		_spCost = skillLearn.getLevelUpSp();
 		_minLevel = skillLearn.getGetLevel();
 		_itemReq = skillLearn.getRequiredItems();
-		_skillRem = skillLearn.getRemoveSkills().stream().map(player::getKnownSkill).filter(Objects::nonNull).collect(Collectors.toList());
+		for (int id : skillLearn.getRemoveSkills())
+		{
+			final Skill removeSkill = player.getKnownSkill(id);
+			if (removeSkill != null)
+			{
+				_skillRem.add(removeSkill);
+			}
+		}
 	}
 	
 	@Override
diff --git a/L2J_Mobius_09.2_ReturnOfTheQueenAnt/java/org/l2jmobius/gameserver/network/serverpackets/ExAcquireSkillInfo.java b/L2J_Mobius_09.2_ReturnOfTheQueenAnt/java/org/l2jmobius/gameserver/network/serverpackets/ExAcquireSkillInfo.java
index 9df735739f..67d8840e92 100644
--- a/L2J_Mobius_09.2_ReturnOfTheQueenAnt/java/org/l2jmobius/gameserver/network/serverpackets/ExAcquireSkillInfo.java
+++ b/L2J_Mobius_09.2_ReturnOfTheQueenAnt/java/org/l2jmobius/gameserver/network/serverpackets/ExAcquireSkillInfo.java
@@ -16,9 +16,8 @@
  */
 package org.l2jmobius.gameserver.network.serverpackets;
 
+import java.util.LinkedList;
 import java.util.List;
-import java.util.Objects;
-import java.util.stream.Collectors;
 
 import org.l2jmobius.gameserver.model.SkillLearn;
 import org.l2jmobius.gameserver.model.actor.Player;
@@ -37,7 +36,7 @@ public class ExAcquireSkillInfo extends ServerPacket
 	private final long _spCost;
 	private final int _minLevel;
 	private final List<List<ItemHolder>> _itemReq;
-	private final List<Skill> _skillRem;
+	private final List<Skill> _skillRem = new LinkedList<>();
 	
 	/**
 	 * Special constructor for Alternate Skill Learning system.<br>
@@ -53,7 +52,14 @@ public class ExAcquireSkillInfo extends ServerPacket
 		_spCost = skillLearn.getLevelUpSp();
 		_minLevel = skillLearn.getGetLevel();
 		_itemReq = skillLearn.getRequiredItems();
-		_skillRem = skillLearn.getRemoveSkills().stream().map(player::getKnownSkill).filter(Objects::nonNull).collect(Collectors.toList());
+		for (int id : skillLearn.getRemoveSkills())
+		{
+			final Skill removeSkill = player.getKnownSkill(id);
+			if (removeSkill != null)
+			{
+				_skillRem.add(removeSkill);
+			}
+		}
 	}
 	
 	@Override
diff --git a/L2J_Mobius_10.2_MasterClass/java/org/l2jmobius/gameserver/network/serverpackets/ExAcquireSkillInfo.java b/L2J_Mobius_10.2_MasterClass/java/org/l2jmobius/gameserver/network/serverpackets/ExAcquireSkillInfo.java
index 9df735739f..67d8840e92 100644
--- a/L2J_Mobius_10.2_MasterClass/java/org/l2jmobius/gameserver/network/serverpackets/ExAcquireSkillInfo.java
+++ b/L2J_Mobius_10.2_MasterClass/java/org/l2jmobius/gameserver/network/serverpackets/ExAcquireSkillInfo.java
@@ -16,9 +16,8 @@
  */
 package org.l2jmobius.gameserver.network.serverpackets;
 
+import java.util.LinkedList;
 import java.util.List;
-import java.util.Objects;
-import java.util.stream.Collectors;
 
 import org.l2jmobius.gameserver.model.SkillLearn;
 import org.l2jmobius.gameserver.model.actor.Player;
@@ -37,7 +36,7 @@ public class ExAcquireSkillInfo extends ServerPacket
 	private final long _spCost;
 	private final int _minLevel;
 	private final List<List<ItemHolder>> _itemReq;
-	private final List<Skill> _skillRem;
+	private final List<Skill> _skillRem = new LinkedList<>();
 	
 	/**
 	 * Special constructor for Alternate Skill Learning system.<br>
@@ -53,7 +52,14 @@ public class ExAcquireSkillInfo extends ServerPacket
 		_spCost = skillLearn.getLevelUpSp();
 		_minLevel = skillLearn.getGetLevel();
 		_itemReq = skillLearn.getRequiredItems();
-		_skillRem = skillLearn.getRemoveSkills().stream().map(player::getKnownSkill).filter(Objects::nonNull).collect(Collectors.toList());
+		for (int id : skillLearn.getRemoveSkills())
+		{
+			final Skill removeSkill = player.getKnownSkill(id);
+			if (removeSkill != null)
+			{
+				_skillRem.add(removeSkill);
+			}
+		}
 	}
 	
 	@Override
diff --git a/L2J_Mobius_10.3_MasterClass/java/org/l2jmobius/gameserver/network/serverpackets/ExAcquireSkillInfo.java b/L2J_Mobius_10.3_MasterClass/java/org/l2jmobius/gameserver/network/serverpackets/ExAcquireSkillInfo.java
index 9df735739f..67d8840e92 100644
--- a/L2J_Mobius_10.3_MasterClass/java/org/l2jmobius/gameserver/network/serverpackets/ExAcquireSkillInfo.java
+++ b/L2J_Mobius_10.3_MasterClass/java/org/l2jmobius/gameserver/network/serverpackets/ExAcquireSkillInfo.java
@@ -16,9 +16,8 @@
  */
 package org.l2jmobius.gameserver.network.serverpackets;
 
+import java.util.LinkedList;
 import java.util.List;
-import java.util.Objects;
-import java.util.stream.Collectors;
 
 import org.l2jmobius.gameserver.model.SkillLearn;
 import org.l2jmobius.gameserver.model.actor.Player;
@@ -37,7 +36,7 @@ public class ExAcquireSkillInfo extends ServerPacket
 	private final long _spCost;
 	private final int _minLevel;
 	private final List<List<ItemHolder>> _itemReq;
-	private final List<Skill> _skillRem;
+	private final List<Skill> _skillRem = new LinkedList<>();
 	
 	/**
 	 * Special constructor for Alternate Skill Learning system.<br>
@@ -53,7 +52,14 @@ public class ExAcquireSkillInfo extends ServerPacket
 		_spCost = skillLearn.getLevelUpSp();
 		_minLevel = skillLearn.getGetLevel();
 		_itemReq = skillLearn.getRequiredItems();
-		_skillRem = skillLearn.getRemoveSkills().stream().map(player::getKnownSkill).filter(Objects::nonNull).collect(Collectors.toList());
+		for (int id : skillLearn.getRemoveSkills())
+		{
+			final Skill removeSkill = player.getKnownSkill(id);
+			if (removeSkill != null)
+			{
+				_skillRem.add(removeSkill);
+			}
+		}
 	}
 	
 	@Override
diff --git a/L2J_Mobius_Classic_1.0/java/org/l2jmobius/gameserver/network/serverpackets/ExAcquireSkillInfo.java b/L2J_Mobius_Classic_1.0/java/org/l2jmobius/gameserver/network/serverpackets/ExAcquireSkillInfo.java
index a1ff065846..9a1d5beb11 100644
--- a/L2J_Mobius_Classic_1.0/java/org/l2jmobius/gameserver/network/serverpackets/ExAcquireSkillInfo.java
+++ b/L2J_Mobius_Classic_1.0/java/org/l2jmobius/gameserver/network/serverpackets/ExAcquireSkillInfo.java
@@ -16,10 +16,9 @@
  */
 package org.l2jmobius.gameserver.network.serverpackets;
 
+import java.util.LinkedList;
 import java.util.List;
-import java.util.Objects;
 import java.util.Set;
-import java.util.stream.Collectors;
 
 import org.l2jmobius.gameserver.model.SkillLearn;
 import org.l2jmobius.gameserver.model.actor.Player;
@@ -38,7 +37,7 @@ public class ExAcquireSkillInfo extends ServerPacket
 	private final long _spCost;
 	private final int _minLevel;
 	private final Set<ItemHolder> _itemReq;
-	private final List<Skill> _skillRem;
+	private final List<Skill> _skillRem = new LinkedList<>();
 	
 	/**
 	 * Special constructor for Alternate Skill Learning system.<br>
@@ -54,7 +53,14 @@ public class ExAcquireSkillInfo extends ServerPacket
 		_spCost = skillLearn.getLevelUpSp();
 		_minLevel = skillLearn.getGetLevel();
 		_itemReq = skillLearn.getRequiredItems();
-		_skillRem = skillLearn.getRemoveSkills().stream().map(player::getKnownSkill).filter(Objects::nonNull).collect(Collectors.toList());
+		for (int id : skillLearn.getRemoveSkills())
+		{
+			final Skill removeSkill = player.getKnownSkill(id);
+			if (removeSkill != null)
+			{
+				_skillRem.add(removeSkill);
+			}
+		}
 	}
 	
 	@Override
diff --git a/L2J_Mobius_Classic_1.5_AgeOfSplendor/java/org/l2jmobius/gameserver/network/serverpackets/ExAcquireSkillInfo.java b/L2J_Mobius_Classic_1.5_AgeOfSplendor/java/org/l2jmobius/gameserver/network/serverpackets/ExAcquireSkillInfo.java
index a1ff065846..9a1d5beb11 100644
--- a/L2J_Mobius_Classic_1.5_AgeOfSplendor/java/org/l2jmobius/gameserver/network/serverpackets/ExAcquireSkillInfo.java
+++ b/L2J_Mobius_Classic_1.5_AgeOfSplendor/java/org/l2jmobius/gameserver/network/serverpackets/ExAcquireSkillInfo.java
@@ -16,10 +16,9 @@
  */
 package org.l2jmobius.gameserver.network.serverpackets;
 
+import java.util.LinkedList;
 import java.util.List;
-import java.util.Objects;
 import java.util.Set;
-import java.util.stream.Collectors;
 
 import org.l2jmobius.gameserver.model.SkillLearn;
 import org.l2jmobius.gameserver.model.actor.Player;
@@ -38,7 +37,7 @@ public class ExAcquireSkillInfo extends ServerPacket
 	private final long _spCost;
 	private final int _minLevel;
 	private final Set<ItemHolder> _itemReq;
-	private final List<Skill> _skillRem;
+	private final List<Skill> _skillRem = new LinkedList<>();
 	
 	/**
 	 * Special constructor for Alternate Skill Learning system.<br>
@@ -54,7 +53,14 @@ public class ExAcquireSkillInfo extends ServerPacket
 		_spCost = skillLearn.getLevelUpSp();
 		_minLevel = skillLearn.getGetLevel();
 		_itemReq = skillLearn.getRequiredItems();
-		_skillRem = skillLearn.getRemoveSkills().stream().map(player::getKnownSkill).filter(Objects::nonNull).collect(Collectors.toList());
+		for (int id : skillLearn.getRemoveSkills())
+		{
+			final Skill removeSkill = player.getKnownSkill(id);
+			if (removeSkill != null)
+			{
+				_skillRem.add(removeSkill);
+			}
+		}
 	}
 	
 	@Override
diff --git a/L2J_Mobius_Classic_2.0_Saviors/java/org/l2jmobius/gameserver/network/serverpackets/ExAcquireSkillInfo.java b/L2J_Mobius_Classic_2.0_Saviors/java/org/l2jmobius/gameserver/network/serverpackets/ExAcquireSkillInfo.java
index a1ff065846..9a1d5beb11 100644
--- a/L2J_Mobius_Classic_2.0_Saviors/java/org/l2jmobius/gameserver/network/serverpackets/ExAcquireSkillInfo.java
+++ b/L2J_Mobius_Classic_2.0_Saviors/java/org/l2jmobius/gameserver/network/serverpackets/ExAcquireSkillInfo.java
@@ -16,10 +16,9 @@
  */
 package org.l2jmobius.gameserver.network.serverpackets;
 
+import java.util.LinkedList;
 import java.util.List;
-import java.util.Objects;
 import java.util.Set;
-import java.util.stream.Collectors;
 
 import org.l2jmobius.gameserver.model.SkillLearn;
 import org.l2jmobius.gameserver.model.actor.Player;
@@ -38,7 +37,7 @@ public class ExAcquireSkillInfo extends ServerPacket
 	private final long _spCost;
 	private final int _minLevel;
 	private final Set<ItemHolder> _itemReq;
-	private final List<Skill> _skillRem;
+	private final List<Skill> _skillRem = new LinkedList<>();
 	
 	/**
 	 * Special constructor for Alternate Skill Learning system.<br>
@@ -54,7 +53,14 @@ public class ExAcquireSkillInfo extends ServerPacket
 		_spCost = skillLearn.getLevelUpSp();
 		_minLevel = skillLearn.getGetLevel();
 		_itemReq = skillLearn.getRequiredItems();
-		_skillRem = skillLearn.getRemoveSkills().stream().map(player::getKnownSkill).filter(Objects::nonNull).collect(Collectors.toList());
+		for (int id : skillLearn.getRemoveSkills())
+		{
+			final Skill removeSkill = player.getKnownSkill(id);
+			if (removeSkill != null)
+			{
+				_skillRem.add(removeSkill);
+			}
+		}
 	}
 	
 	@Override
diff --git a/L2J_Mobius_Classic_2.5_Zaken/java/org/l2jmobius/gameserver/network/serverpackets/ExAcquireSkillInfo.java b/L2J_Mobius_Classic_2.5_Zaken/java/org/l2jmobius/gameserver/network/serverpackets/ExAcquireSkillInfo.java
index a1ff065846..9a1d5beb11 100644
--- a/L2J_Mobius_Classic_2.5_Zaken/java/org/l2jmobius/gameserver/network/serverpackets/ExAcquireSkillInfo.java
+++ b/L2J_Mobius_Classic_2.5_Zaken/java/org/l2jmobius/gameserver/network/serverpackets/ExAcquireSkillInfo.java
@@ -16,10 +16,9 @@
  */
 package org.l2jmobius.gameserver.network.serverpackets;
 
+import java.util.LinkedList;
 import java.util.List;
-import java.util.Objects;
 import java.util.Set;
-import java.util.stream.Collectors;
 
 import org.l2jmobius.gameserver.model.SkillLearn;
 import org.l2jmobius.gameserver.model.actor.Player;
@@ -38,7 +37,7 @@ public class ExAcquireSkillInfo extends ServerPacket
 	private final long _spCost;
 	private final int _minLevel;
 	private final Set<ItemHolder> _itemReq;
-	private final List<Skill> _skillRem;
+	private final List<Skill> _skillRem = new LinkedList<>();
 	
 	/**
 	 * Special constructor for Alternate Skill Learning system.<br>
@@ -54,7 +53,14 @@ public class ExAcquireSkillInfo extends ServerPacket
 		_spCost = skillLearn.getLevelUpSp();
 		_minLevel = skillLearn.getGetLevel();
 		_itemReq = skillLearn.getRequiredItems();
-		_skillRem = skillLearn.getRemoveSkills().stream().map(player::getKnownSkill).filter(Objects::nonNull).collect(Collectors.toList());
+		for (int id : skillLearn.getRemoveSkills())
+		{
+			final Skill removeSkill = player.getKnownSkill(id);
+			if (removeSkill != null)
+			{
+				_skillRem.add(removeSkill);
+			}
+		}
 	}
 	
 	@Override
diff --git a/L2J_Mobius_Classic_2.7_Antharas/java/org/l2jmobius/gameserver/network/serverpackets/ExAcquireSkillInfo.java b/L2J_Mobius_Classic_2.7_Antharas/java/org/l2jmobius/gameserver/network/serverpackets/ExAcquireSkillInfo.java
index a1ff065846..9a1d5beb11 100644
--- a/L2J_Mobius_Classic_2.7_Antharas/java/org/l2jmobius/gameserver/network/serverpackets/ExAcquireSkillInfo.java
+++ b/L2J_Mobius_Classic_2.7_Antharas/java/org/l2jmobius/gameserver/network/serverpackets/ExAcquireSkillInfo.java
@@ -16,10 +16,9 @@
  */
 package org.l2jmobius.gameserver.network.serverpackets;
 
+import java.util.LinkedList;
 import java.util.List;
-import java.util.Objects;
 import java.util.Set;
-import java.util.stream.Collectors;
 
 import org.l2jmobius.gameserver.model.SkillLearn;
 import org.l2jmobius.gameserver.model.actor.Player;
@@ -38,7 +37,7 @@ public class ExAcquireSkillInfo extends ServerPacket
 	private final long _spCost;
 	private final int _minLevel;
 	private final Set<ItemHolder> _itemReq;
-	private final List<Skill> _skillRem;
+	private final List<Skill> _skillRem = new LinkedList<>();
 	
 	/**
 	 * Special constructor for Alternate Skill Learning system.<br>
@@ -54,7 +53,14 @@ public class ExAcquireSkillInfo extends ServerPacket
 		_spCost = skillLearn.getLevelUpSp();
 		_minLevel = skillLearn.getGetLevel();
 		_itemReq = skillLearn.getRequiredItems();
-		_skillRem = skillLearn.getRemoveSkills().stream().map(player::getKnownSkill).filter(Objects::nonNull).collect(Collectors.toList());
+		for (int id : skillLearn.getRemoveSkills())
+		{
+			final Skill removeSkill = player.getKnownSkill(id);
+			if (removeSkill != null)
+			{
+				_skillRem.add(removeSkill);
+			}
+		}
 	}
 	
 	@Override
diff --git a/L2J_Mobius_Classic_2.8_SevenSigns/java/org/l2jmobius/gameserver/network/serverpackets/ExAcquireSkillInfo.java b/L2J_Mobius_Classic_2.8_SevenSigns/java/org/l2jmobius/gameserver/network/serverpackets/ExAcquireSkillInfo.java
index a1ff065846..9a1d5beb11 100644
--- a/L2J_Mobius_Classic_2.8_SevenSigns/java/org/l2jmobius/gameserver/network/serverpackets/ExAcquireSkillInfo.java
+++ b/L2J_Mobius_Classic_2.8_SevenSigns/java/org/l2jmobius/gameserver/network/serverpackets/ExAcquireSkillInfo.java
@@ -16,10 +16,9 @@
  */
 package org.l2jmobius.gameserver.network.serverpackets;
 
+import java.util.LinkedList;
 import java.util.List;
-import java.util.Objects;
 import java.util.Set;
-import java.util.stream.Collectors;
 
 import org.l2jmobius.gameserver.model.SkillLearn;
 import org.l2jmobius.gameserver.model.actor.Player;
@@ -38,7 +37,7 @@ public class ExAcquireSkillInfo extends ServerPacket
 	private final long _spCost;
 	private final int _minLevel;
 	private final Set<ItemHolder> _itemReq;
-	private final List<Skill> _skillRem;
+	private final List<Skill> _skillRem = new LinkedList<>();
 	
 	/**
 	 * Special constructor for Alternate Skill Learning system.<br>
@@ -54,7 +53,14 @@ public class ExAcquireSkillInfo extends ServerPacket
 		_spCost = skillLearn.getLevelUpSp();
 		_minLevel = skillLearn.getGetLevel();
 		_itemReq = skillLearn.getRequiredItems();
-		_skillRem = skillLearn.getRemoveSkills().stream().map(player::getKnownSkill).filter(Objects::nonNull).collect(Collectors.toList());
+		for (int id : skillLearn.getRemoveSkills())
+		{
+			final Skill removeSkill = player.getKnownSkill(id);
+			if (removeSkill != null)
+			{
+				_skillRem.add(removeSkill);
+			}
+		}
 	}
 	
 	@Override
diff --git a/L2J_Mobius_Classic_2.9.5_Saviors/java/org/l2jmobius/gameserver/network/serverpackets/ExAcquireSkillInfo.java b/L2J_Mobius_Classic_2.9.5_Saviors/java/org/l2jmobius/gameserver/network/serverpackets/ExAcquireSkillInfo.java
index a1ff065846..9a1d5beb11 100644
--- a/L2J_Mobius_Classic_2.9.5_Saviors/java/org/l2jmobius/gameserver/network/serverpackets/ExAcquireSkillInfo.java
+++ b/L2J_Mobius_Classic_2.9.5_Saviors/java/org/l2jmobius/gameserver/network/serverpackets/ExAcquireSkillInfo.java
@@ -16,10 +16,9 @@
  */
 package org.l2jmobius.gameserver.network.serverpackets;
 
+import java.util.LinkedList;
 import java.util.List;
-import java.util.Objects;
 import java.util.Set;
-import java.util.stream.Collectors;
 
 import org.l2jmobius.gameserver.model.SkillLearn;
 import org.l2jmobius.gameserver.model.actor.Player;
@@ -38,7 +37,7 @@ public class ExAcquireSkillInfo extends ServerPacket
 	private final long _spCost;
 	private final int _minLevel;
 	private final Set<ItemHolder> _itemReq;
-	private final List<Skill> _skillRem;
+	private final List<Skill> _skillRem = new LinkedList<>();
 	
 	/**
 	 * Special constructor for Alternate Skill Learning system.<br>
@@ -54,7 +53,14 @@ public class ExAcquireSkillInfo extends ServerPacket
 		_spCost = skillLearn.getLevelUpSp();
 		_minLevel = skillLearn.getGetLevel();
 		_itemReq = skillLearn.getRequiredItems();
-		_skillRem = skillLearn.getRemoveSkills().stream().map(player::getKnownSkill).filter(Objects::nonNull).collect(Collectors.toList());
+		for (int id : skillLearn.getRemoveSkills())
+		{
+			final Skill removeSkill = player.getKnownSkill(id);
+			if (removeSkill != null)
+			{
+				_skillRem.add(removeSkill);
+			}
+		}
 	}
 	
 	@Override
diff --git a/L2J_Mobius_Classic_2.9_SecretOfEmpire/java/org/l2jmobius/gameserver/network/serverpackets/ExAcquireSkillInfo.java b/L2J_Mobius_Classic_2.9_SecretOfEmpire/java/org/l2jmobius/gameserver/network/serverpackets/ExAcquireSkillInfo.java
index a1ff065846..9a1d5beb11 100644
--- a/L2J_Mobius_Classic_2.9_SecretOfEmpire/java/org/l2jmobius/gameserver/network/serverpackets/ExAcquireSkillInfo.java
+++ b/L2J_Mobius_Classic_2.9_SecretOfEmpire/java/org/l2jmobius/gameserver/network/serverpackets/ExAcquireSkillInfo.java
@@ -16,10 +16,9 @@
  */
 package org.l2jmobius.gameserver.network.serverpackets;
 
+import java.util.LinkedList;
 import java.util.List;
-import java.util.Objects;
 import java.util.Set;
-import java.util.stream.Collectors;
 
 import org.l2jmobius.gameserver.model.SkillLearn;
 import org.l2jmobius.gameserver.model.actor.Player;
@@ -38,7 +37,7 @@ public class ExAcquireSkillInfo extends ServerPacket
 	private final long _spCost;
 	private final int _minLevel;
 	private final Set<ItemHolder> _itemReq;
-	private final List<Skill> _skillRem;
+	private final List<Skill> _skillRem = new LinkedList<>();
 	
 	/**
 	 * Special constructor for Alternate Skill Learning system.<br>
@@ -54,7 +53,14 @@ public class ExAcquireSkillInfo extends ServerPacket
 		_spCost = skillLearn.getLevelUpSp();
 		_minLevel = skillLearn.getGetLevel();
 		_itemReq = skillLearn.getRequiredItems();
-		_skillRem = skillLearn.getRemoveSkills().stream().map(player::getKnownSkill).filter(Objects::nonNull).collect(Collectors.toList());
+		for (int id : skillLearn.getRemoveSkills())
+		{
+			final Skill removeSkill = player.getKnownSkill(id);
+			if (removeSkill != null)
+			{
+				_skillRem.add(removeSkill);
+			}
+		}
 	}
 	
 	@Override
diff --git a/L2J_Mobius_Classic_3.0_TheKamael/java/org/l2jmobius/gameserver/network/serverpackets/ExAcquireSkillInfo.java b/L2J_Mobius_Classic_3.0_TheKamael/java/org/l2jmobius/gameserver/network/serverpackets/ExAcquireSkillInfo.java
index a1ff065846..9a1d5beb11 100644
--- a/L2J_Mobius_Classic_3.0_TheKamael/java/org/l2jmobius/gameserver/network/serverpackets/ExAcquireSkillInfo.java
+++ b/L2J_Mobius_Classic_3.0_TheKamael/java/org/l2jmobius/gameserver/network/serverpackets/ExAcquireSkillInfo.java
@@ -16,10 +16,9 @@
  */
 package org.l2jmobius.gameserver.network.serverpackets;
 
+import java.util.LinkedList;
 import java.util.List;
-import java.util.Objects;
 import java.util.Set;
-import java.util.stream.Collectors;
 
 import org.l2jmobius.gameserver.model.SkillLearn;
 import org.l2jmobius.gameserver.model.actor.Player;
@@ -38,7 +37,7 @@ public class ExAcquireSkillInfo extends ServerPacket
 	private final long _spCost;
 	private final int _minLevel;
 	private final Set<ItemHolder> _itemReq;
-	private final List<Skill> _skillRem;
+	private final List<Skill> _skillRem = new LinkedList<>();
 	
 	/**
 	 * Special constructor for Alternate Skill Learning system.<br>
@@ -54,7 +53,14 @@ public class ExAcquireSkillInfo extends ServerPacket
 		_spCost = skillLearn.getLevelUpSp();
 		_minLevel = skillLearn.getGetLevel();
 		_itemReq = skillLearn.getRequiredItems();
-		_skillRem = skillLearn.getRemoveSkills().stream().map(player::getKnownSkill).filter(Objects::nonNull).collect(Collectors.toList());
+		for (int id : skillLearn.getRemoveSkills())
+		{
+			final Skill removeSkill = player.getKnownSkill(id);
+			if (removeSkill != null)
+			{
+				_skillRem.add(removeSkill);
+			}
+		}
 	}
 	
 	@Override
diff --git a/L2J_Mobius_Classic_Interlude/java/org/l2jmobius/gameserver/network/serverpackets/ExAcquireSkillInfo.java b/L2J_Mobius_Classic_Interlude/java/org/l2jmobius/gameserver/network/serverpackets/ExAcquireSkillInfo.java
index a1ff065846..9a1d5beb11 100644
--- a/L2J_Mobius_Classic_Interlude/java/org/l2jmobius/gameserver/network/serverpackets/ExAcquireSkillInfo.java
+++ b/L2J_Mobius_Classic_Interlude/java/org/l2jmobius/gameserver/network/serverpackets/ExAcquireSkillInfo.java
@@ -16,10 +16,9 @@
  */
 package org.l2jmobius.gameserver.network.serverpackets;
 
+import java.util.LinkedList;
 import java.util.List;
-import java.util.Objects;
 import java.util.Set;
-import java.util.stream.Collectors;
 
 import org.l2jmobius.gameserver.model.SkillLearn;
 import org.l2jmobius.gameserver.model.actor.Player;
@@ -38,7 +37,7 @@ public class ExAcquireSkillInfo extends ServerPacket
 	private final long _spCost;
 	private final int _minLevel;
 	private final Set<ItemHolder> _itemReq;
-	private final List<Skill> _skillRem;
+	private final List<Skill> _skillRem = new LinkedList<>();
 	
 	/**
 	 * Special constructor for Alternate Skill Learning system.<br>
@@ -54,7 +53,14 @@ public class ExAcquireSkillInfo extends ServerPacket
 		_spCost = skillLearn.getLevelUpSp();
 		_minLevel = skillLearn.getGetLevel();
 		_itemReq = skillLearn.getRequiredItems();
-		_skillRem = skillLearn.getRemoveSkills().stream().map(player::getKnownSkill).filter(Objects::nonNull).collect(Collectors.toList());
+		for (int id : skillLearn.getRemoveSkills())
+		{
+			final Skill removeSkill = player.getKnownSkill(id);
+			if (removeSkill != null)
+			{
+				_skillRem.add(removeSkill);
+			}
+		}
 	}
 	
 	@Override
diff --git a/L2J_Mobius_Essence_4.2_DwellingOfSpirits/java/org/l2jmobius/gameserver/network/serverpackets/ExAcquireSkillInfo.java b/L2J_Mobius_Essence_4.2_DwellingOfSpirits/java/org/l2jmobius/gameserver/network/serverpackets/ExAcquireSkillInfo.java
index 9df735739f..67d8840e92 100644
--- a/L2J_Mobius_Essence_4.2_DwellingOfSpirits/java/org/l2jmobius/gameserver/network/serverpackets/ExAcquireSkillInfo.java
+++ b/L2J_Mobius_Essence_4.2_DwellingOfSpirits/java/org/l2jmobius/gameserver/network/serverpackets/ExAcquireSkillInfo.java
@@ -16,9 +16,8 @@
  */
 package org.l2jmobius.gameserver.network.serverpackets;
 
+import java.util.LinkedList;
 import java.util.List;
-import java.util.Objects;
-import java.util.stream.Collectors;
 
 import org.l2jmobius.gameserver.model.SkillLearn;
 import org.l2jmobius.gameserver.model.actor.Player;
@@ -37,7 +36,7 @@ public class ExAcquireSkillInfo extends ServerPacket
 	private final long _spCost;
 	private final int _minLevel;
 	private final List<List<ItemHolder>> _itemReq;
-	private final List<Skill> _skillRem;
+	private final List<Skill> _skillRem = new LinkedList<>();
 	
 	/**
 	 * Special constructor for Alternate Skill Learning system.<br>
@@ -53,7 +52,14 @@ public class ExAcquireSkillInfo extends ServerPacket
 		_spCost = skillLearn.getLevelUpSp();
 		_minLevel = skillLearn.getGetLevel();
 		_itemReq = skillLearn.getRequiredItems();
-		_skillRem = skillLearn.getRemoveSkills().stream().map(player::getKnownSkill).filter(Objects::nonNull).collect(Collectors.toList());
+		for (int id : skillLearn.getRemoveSkills())
+		{
+			final Skill removeSkill = player.getKnownSkill(id);
+			if (removeSkill != null)
+			{
+				_skillRem.add(removeSkill);
+			}
+		}
 	}
 	
 	@Override
diff --git a/L2J_Mobius_Essence_5.2_FrostLord/java/org/l2jmobius/gameserver/network/serverpackets/ExAcquireSkillInfo.java b/L2J_Mobius_Essence_5.2_FrostLord/java/org/l2jmobius/gameserver/network/serverpackets/ExAcquireSkillInfo.java
index 9df735739f..67d8840e92 100644
--- a/L2J_Mobius_Essence_5.2_FrostLord/java/org/l2jmobius/gameserver/network/serverpackets/ExAcquireSkillInfo.java
+++ b/L2J_Mobius_Essence_5.2_FrostLord/java/org/l2jmobius/gameserver/network/serverpackets/ExAcquireSkillInfo.java
@@ -16,9 +16,8 @@
  */
 package org.l2jmobius.gameserver.network.serverpackets;
 
+import java.util.LinkedList;
 import java.util.List;
-import java.util.Objects;
-import java.util.stream.Collectors;
 
 import org.l2jmobius.gameserver.model.SkillLearn;
 import org.l2jmobius.gameserver.model.actor.Player;
@@ -37,7 +36,7 @@ public class ExAcquireSkillInfo extends ServerPacket
 	private final long _spCost;
 	private final int _minLevel;
 	private final List<List<ItemHolder>> _itemReq;
-	private final List<Skill> _skillRem;
+	private final List<Skill> _skillRem = new LinkedList<>();
 	
 	/**
 	 * Special constructor for Alternate Skill Learning system.<br>
@@ -53,7 +52,14 @@ public class ExAcquireSkillInfo extends ServerPacket
 		_spCost = skillLearn.getLevelUpSp();
 		_minLevel = skillLearn.getGetLevel();
 		_itemReq = skillLearn.getRequiredItems();
-		_skillRem = skillLearn.getRemoveSkills().stream().map(player::getKnownSkill).filter(Objects::nonNull).collect(Collectors.toList());
+		for (int id : skillLearn.getRemoveSkills())
+		{
+			final Skill removeSkill = player.getKnownSkill(id);
+			if (removeSkill != null)
+			{
+				_skillRem.add(removeSkill);
+			}
+		}
 	}
 	
 	@Override
diff --git a/L2J_Mobius_Essence_6.2_Vanguard/java/org/l2jmobius/gameserver/network/serverpackets/ExAcquireSkillInfo.java b/L2J_Mobius_Essence_6.2_Vanguard/java/org/l2jmobius/gameserver/network/serverpackets/ExAcquireSkillInfo.java
index 9df735739f..67d8840e92 100644
--- a/L2J_Mobius_Essence_6.2_Vanguard/java/org/l2jmobius/gameserver/network/serverpackets/ExAcquireSkillInfo.java
+++ b/L2J_Mobius_Essence_6.2_Vanguard/java/org/l2jmobius/gameserver/network/serverpackets/ExAcquireSkillInfo.java
@@ -16,9 +16,8 @@
  */
 package org.l2jmobius.gameserver.network.serverpackets;
 
+import java.util.LinkedList;
 import java.util.List;
-import java.util.Objects;
-import java.util.stream.Collectors;
 
 import org.l2jmobius.gameserver.model.SkillLearn;
 import org.l2jmobius.gameserver.model.actor.Player;
@@ -37,7 +36,7 @@ public class ExAcquireSkillInfo extends ServerPacket
 	private final long _spCost;
 	private final int _minLevel;
 	private final List<List<ItemHolder>> _itemReq;
-	private final List<Skill> _skillRem;
+	private final List<Skill> _skillRem = new LinkedList<>();
 	
 	/**
 	 * Special constructor for Alternate Skill Learning system.<br>
@@ -53,7 +52,14 @@ public class ExAcquireSkillInfo extends ServerPacket
 		_spCost = skillLearn.getLevelUpSp();
 		_minLevel = skillLearn.getGetLevel();
 		_itemReq = skillLearn.getRequiredItems();
-		_skillRem = skillLearn.getRemoveSkills().stream().map(player::getKnownSkill).filter(Objects::nonNull).collect(Collectors.toList());
+		for (int id : skillLearn.getRemoveSkills())
+		{
+			final Skill removeSkill = player.getKnownSkill(id);
+			if (removeSkill != null)
+			{
+				_skillRem.add(removeSkill);
+			}
+		}
 	}
 	
 	@Override
diff --git a/L2J_Mobius_Essence_6.3_Crusader/java/org/l2jmobius/gameserver/network/serverpackets/ExAcquireSkillInfo.java b/L2J_Mobius_Essence_6.3_Crusader/java/org/l2jmobius/gameserver/network/serverpackets/ExAcquireSkillInfo.java
index 9df735739f..67d8840e92 100644
--- a/L2J_Mobius_Essence_6.3_Crusader/java/org/l2jmobius/gameserver/network/serverpackets/ExAcquireSkillInfo.java
+++ b/L2J_Mobius_Essence_6.3_Crusader/java/org/l2jmobius/gameserver/network/serverpackets/ExAcquireSkillInfo.java
@@ -16,9 +16,8 @@
  */
 package org.l2jmobius.gameserver.network.serverpackets;
 
+import java.util.LinkedList;
 import java.util.List;
-import java.util.Objects;
-import java.util.stream.Collectors;
 
 import org.l2jmobius.gameserver.model.SkillLearn;
 import org.l2jmobius.gameserver.model.actor.Player;
@@ -37,7 +36,7 @@ public class ExAcquireSkillInfo extends ServerPacket
 	private final long _spCost;
 	private final int _minLevel;
 	private final List<List<ItemHolder>> _itemReq;
-	private final List<Skill> _skillRem;
+	private final List<Skill> _skillRem = new LinkedList<>();
 	
 	/**
 	 * Special constructor for Alternate Skill Learning system.<br>
@@ -53,7 +52,14 @@ public class ExAcquireSkillInfo extends ServerPacket
 		_spCost = skillLearn.getLevelUpSp();
 		_minLevel = skillLearn.getGetLevel();
 		_itemReq = skillLearn.getRequiredItems();
-		_skillRem = skillLearn.getRemoveSkills().stream().map(player::getKnownSkill).filter(Objects::nonNull).collect(Collectors.toList());
+		for (int id : skillLearn.getRemoveSkills())
+		{
+			final Skill removeSkill = player.getKnownSkill(id);
+			if (removeSkill != null)
+			{
+				_skillRem.add(removeSkill);
+			}
+		}
 	}
 	
 	@Override