-Misc clean up/refactor.

-Removed unnecessary Map.containsKey calls
-Using java 8 methods where possible to avoid external checks.

Source L2J HighFive branch:
9d0fee8537

trunk/java/com/l2jserver/gameserver/instancemanager/RaidBossSpawnManager.java

@@ -176,13 +176,12 @@ public class RaidBossSpawnManager
 	 */
 	public void updateStatus(L2RaidBossInstance boss, boolean isBossDead)
 	{
-		if (!_storedInfo.containsKey(boss.getId()))
+		final StatsSet info = _storedInfo.get(boss.getId());
+		if (info == null)
 		{
 			return;
 		}
 		
-		final StatsSet info = _storedInfo.get(boss.getId());
-		
 		if (isBossDead)
 		{
 			boss.setRaidStatus(StatusEnum.DEAD);