Problem java.lang.OutOfMemoryError: Java heap space

[Baron]

I keep on getting this error every now and then. The problem is its not even out of memory.

Exception in thread "Thread-198" java.lang.OutOfMemoryError: Java heap space
Exception in thread "process reaper" java.lang.OutOfMemoryError: GC overhead limit exceeded
Exception in thread "main" java.lang.OutOfMemoryError: GC overhead limit exceeded
Exception in thread "Thread-3" java.lang.OutOfMemoryError: Java heap space

OS: Ubuntu 12.04.2 LTS 64bit
Players: 24-32 on at one time

Java:
java version "1.7.0_13"
Java(TM) SE Runtime Environment (build 1.7.0_13-b20)
Java HotSpot(TM) 64-Bit Server VM (build 23.7-b01, mixed mode)

Bat file settings:

java -server -Xincgc -Xmn2G -Xmx12G -XX\:PermSize\=128m -XX\:MaxPermSize\=256m -XX\:+DisableExplicitGC -XX\:+CMSIncrementalMode -XX\:+CMSIncrementalPacing -XX\:+UseConcMarkSweepGC -XX\:+UseParNewGC -XX\:+CMSParallelRemarkEnabled -XX\:MaxGCPauseMillis\=50 -XX\:+UseAdaptiveGCBoundary -XX\:+UseCMSCompactAtFullCollection -XX\:ParallelGCThreads\=8 -XX\:MaxTenuringThreshold\=15 -XX\:UseSSE\=4 -XX\:+UseLargePages -XX\:+UseFastAccessorMethods -XX\:+UseStringCache -XX\:ReservedCodeCacheSize\=1G -XX\:+UseCompressedOops -XX\:CMSFullGCsBeforeCompaction\=1 -XX\:+OptimizeStringConcat -Xnoclassgc -oss4M -ss4M -XX\:+AggressiveOpts -Djline.terminal\=jline.UnsupportedTerminal

How can I fix this problem and improve server performance as my server is becoming more popular everyday.

Some more stats:
15:57:11 [INFO] Current TPS = 20.0
15:57:11 [INFO] Maximum memory: 12,083 MB.
15:57:11 [INFO] Allocated memory: 2,343 MB.
15:57:11 [INFO] Free memory: 1,155 MB.
15:57:11 [INFO] World "spawn": 2,581 chunks, 2,050 entities.
15:57:11 [INFO] World "world_twilightforest": 0 chunks, 0 entities.
15:57:11 [INFO] The End "spawn_the_end": 0 chunks, 0 entities.
15:57:11 [INFO] Nether "spawn_nether": 0 chunks, 0 entities.
15:57:11 [INFO] World "world": 291 chunks, 66 entities.
15:58:13 [INFO] There are 18 out of maximum 42 players online.

 

[Dingham]

This is a memory leak, currently suffering this myself.

Need to uninstall chicken chunkloaders to fix

 

[Baron]

This is a memory leak, currently suffering this myself.

Need to uninstall chicken chunkloaders to fix

You sure chicken chunks is the problem as no one should be able to get it on my server since its blocked unless your op.

 

[Dingham]

I uninstalled on my test server and the was a noticeable increase in performance.Also memory leak message went

 

[Dekar]

How much memory does your server have?
Have you tried running with basic java arguments instead of all the extra ones you are currently using?

 

[Baron]

How much memory does your server have?
Have you tried running with basic java arguments instead of all the extra ones you are currently using?

32GBs of ram. No I haven't tried the basic java arguments.