Server Crashes Randomly: OutOfMemoryError with 4GB

I've had this issue for around 3 days now, and I'm unsure what is causing it. I've updated my CraftBukkit dev build already, and that solved nothing. I would like to mention that this error was not in existence until after updating to 1.5.1. I am currently running CB #2718, however, the last one I was running which also had this same issue was CB #2706. The error is below, however, there are a few things I would like to point out from this:

• Immediately after /home castle, the server crashed. This is an essentials command, however, I am unsure whether or not the issue is in fact essentials.
• Immediately after that, I typed "online" into the console, notice how it did not yield any result
• Notice after that, Glizer says there are still two players online, which is false, being both players got kicked from the server after the crash. This tells me the server is still responding partially. There is one difference, when server is functioning normally, it generally says [INFO] /84.200.150.231:45934 lost connection after every heartbeat.
• I tried another command "nolagg examine 10," one that is not essentials, it also failed to yield any output
• Large error mentioning EbanBackgroundThread and OutOfMemoryError. I would like to note, that on every server startup, I do get the error [SEVERE] ebean.properties not found, so could this be the root of the issue? I would like to think not, being I've had this error since long before 1.5.1.
• Lastly it mentions BkCommonLib and Chairs, which I am not 100% sure are responsible for this, however, I am willing to remove them both.

Code:

2013-03-30 01:06:51 [INFO] TH3_RAABI issued server command: /home castle
online
2013-03-30 01:10:22 [INFO] [glizer] Saving banqueue
2013-03-30 01:10:23 [INFO] [glizer] Heartbeat, Online Players: 2
online
permtest
nolagg examine 10
2013-03-30 01:13:55 [SEVERE] Exception in thread "EbeanBackgroundThread"
2013-03-30 01:14:03 [SEVERE] java.lang.OutOfMemoryError: Java heap space
2013-03-30 01:14:25 [SEVERE]at java.util.Vector.iterator(Vector.java:1114)
2013-03-30 01:14:28 [SEVERE]at com.avaje.ebeaninternal.server.lib.BackgroundThread$Runner.runJobs(BackgroundThread.java:191)
2013-03-30 01:14:28 [SEVERE]at com.avaje.ebeaninternal.server.lib.BackgroundThread$Runner.run(BackgroundThread.java:172)
2013-03-30 01:14:32 [SEVERE]at java.lang.Thread.run(Thread.java:722)
2013-03-30 01:14:38 [SEVERE] Exception in thread "Listen thread"
2013-03-30 01:14:42 [SEVERE] java.lang.OutOfMemoryError: Java heap space
2013-03-30 01:15:31 [INFO] [glizer] Saving banqueue
2013-03-30 01:16:41 [SEVERE] Exception in thread "Thread-15"
2013-03-30 01:17:40 [SEVERE] java.lang.OutOfMemoryError: Java heap space
2013-03-30 01:18:18 [SEVERE] Exception in thread "Snooper Timer"
2013-03-30 01:18:39 [SEVERE] java.lang.OutOfMemoryError: Java heap space
2013-03-30 01:18:39 [INFO] [glizer] Heartbeat cancelled, attempting to restart it.
2013-03-30 01:19:33 [INFO] [glizer] Saving banqueue
2013-03-30 01:21:03 [SEVERE] Exception in thread "Thread-73"
2013-03-30 01:21:10 [SEVERE] java.lang.OutOfMemoryError: Java heap space
2013-03-30 01:21:12 [SEVERE] Exception in thread "Thread-11"
2013-03-30 01:21:12 [SEVERE] java.lang.OutOfMemoryError: Java heap space
2013-03-30 01:21:14 [SEVERE] Exception in thread "AWT-EventQueue-0"
2013-03-30 01:21:19 [SEVERE] java.lang.OutOfMemoryError: Java heap space
2013-03-30 01:21:20 [SEVERE] Exception in thread "Thread-31"
2013-03-30 01:21:30 [SEVERE] Exception in thread "TimerQueue"
2013-03-30 01:21:35 [SEVERE] java.lang.OutOfMemoryError: Java heap space
2013-03-30 01:21:50 [SEVERE] Exception in thread "Thread-16"
2013-03-30 01:21:54 [SEVERE] java.lang.OutOfMemoryError: Java heap space
2013-03-30 01:22:11 [SEVERE] java.lang.OutOfMemoryError: Java heap space
2013-03-30 01:22:22 [SEVERE] java.lang.OutOfMemoryError: Java heap space
2013-03-30 01:22:26 [SEVERE] Encountered an unexpected exception OutOfMemoryError
java.lang.OutOfMemoryError: Java heap space
2013-03-30 01:22:27 [WARNING] [Server] The main thread failed to respond after 10 seconds
2013-03-30 01:22:29 [WARNING] [Server] Probable Plugin causes: 'BKCommonLib and Chairs'
2013-03-30 01:22:29 [WARNING] [Server] What follows is the stack trace of the main thread

Stacktrace:

Code:

---- Minecraft Crash Report ----
// You're mean.
 
Time: 3/30/13 1:24 AM
Description: Exception in server tick loop
 
java.lang.OutOfMemoryError: Java heap space
 
 
A detailed walkthrough of the error, its code path and all known details is as follows:
---------------------------------------------------------------------------------------
 
-- System Details --
Details:
Minecraft Version: 1.5.1
Operating System: Linux (amd64) version 3.2.0-35-generic
Java Version: 1.7.0_07, Oracle Corporation
Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Oracle Corporation
Memory: 409618784 bytes (390 MB) / 3878420480 bytes (3698 MB) up to 3878420480 bytes (3698 MB)
JVM Flags: 2 total; -Xms4G -Xmx4G
AABB Pool Size: 859095 (48109320 bytes; 45 MB) allocated, 859095 (48109320 bytes; 45 MB) used
Suspicious classes: ~~ERROR~~ OutOfMemoryError: Java heap space
IntCache: cache: 0, tcache: 0, allocated: 3, tallocated: 63
CraftBukkit Information: ~~ERROR~~ OutOfMemoryError: Java heap space
Profiler Position: N/A (disabled)
Vec3 Pool Size: ~~ERROR~~ NullPointerException: null
Player Count: 2 / 30; [EntityPlayer['Chadward27'/1194, l='Frisnuk', x=414.13, y=150.00, z=307.20](Chadward27 at 414.12729486096487,150.0,307.2025067790195), EntityPlayer['TH3_RAABI'/2470, l='Frisnuk', x=1246.70, y=92.00, z=-1038.21](TH3_RAABI at 1246.699999988079,92.0,-1038.2100364083296)]
Is Modded: Definitely; Server brand changed to 'craftbukkit'
Type: Dedicated Server (map_server.txt)

ANY support at all would be greatly appreciated. Removing plugins one by one to figure out what the issue is, is not an option. I have 70 plugins, and being this error randomly happens (sometimes taking a few minutes, sometimes several hours), it would be too difficult to see which plugin is problematic. Thank you in advanced.

 

startup log would be nice.

 

I've updated Chairs and removed my packet generation code. It now utilizes ProtocolLib methods instead.