Every time I log on to my server, it crashed after a few seconds or minute and its from the Minecraft Watchdog. I've tried to remove entities and other things, but no luck.

---- Minecraft Crash Report ----
// Would you like a cupcake?

Time: 1/18/16 3:25 PM
Description: Watching Server

java.lang.Error
at com.google.common.collect.AbstractIterator.hasNext(AbstractIterator.java:138)
at asb.a(SourceFile:738)
at ahp.a(SourceFile:2311)
at o.a(SourceFile:464)
at o.b(SourceFile:141)
at j.a(SourceFile:51)
at ahf.a(SourceFile:105)
at akg.b(SourceFile:101)
at lp.a(SourceFile:646)
at lp.d(SourceFile:215)
at net.minecraft.server.MinecraftServer.D(SourceFile:616)
at la.D(SourceFile:339)
at net.minecraft.server.MinecraftServer.C(SourceFile:552)
at net.minecraft.server.MinecraftServer.run(SourceFile:456)
at java.lang.Thread.run(Thread.java:745)

A detailed walkthrough of the error, its code path and all known details is as follows:
---------------------------------------------------------------------------------------

– Head –
Stacktrace:
at com.google.common.collect.AbstractIterator.hasNext(AbstractIterator.java:138)
at asb.a(SourceFile:738)
at ahp.a(SourceFile:2311)
at o.a(SourceFile:464)
at o.b(SourceFile:141)
at j.a(SourceFile:51)
at ahf.a(SourceFile:105)
at akg.b(SourceFile:101)
at lp.a(SourceFile:646)
at lp.d(SourceFile:215)
at net.minecraft.server.MinecraftServer.D(SourceFile:616)
at la.D(SourceFile:339)
at net.minecraft.server.MinecraftServer.C(SourceFile:552)

– Thread Dump –
Details:
Threads: "File IO Thread" Id=51 TIMED_WAITING
at java.lang.Thread.sleep(Native Method)
at bba.c(SourceFile:44)
at bba.run(SourceFile:30)
at java.lang.Thread.run(Thread.java:745)

"Netty Epoll Server IO #3" Id=22 RUNNABLE
at io.netty.channel.epoll.Native.epollWait(Native Method)
at io.netty.channel.epoll.EpollEventLoop.epollWait(EpollEventLoop.java:194)
at io.netty.channel.epoll.EpollEventLoop.run(EpollEventLoop.java:219)
at io.netty.util.concurrent.SingleThreadEventExecutor$2.run(SingleThreadEventExecutor.java:116)
at java.lang.Thread.run(Thread.java:745)

"Netty Epoll Server IO #2" Id=21 RUNNABLE (in native)
at io.netty.channel.epoll.Native.epollWait(Native Method)
at io.netty.channel.epoll.EpollEventLoop.epollWait(EpollEventLoop.java:194)
at io.netty.channel.epoll.EpollEventLoop.run(EpollEventLoop.java:219)
at io.netty.util.concurrent.SingleThreadEventExecutor$2.run(SingleThreadEventExecutor.java:116)
at java.lang.Thread.run(Thread.java:745)

"Java2D Disposer" Id=45 WAITING on java.lang.ref.ReferenceQueue$Lock@3dd1b6dc
at java.lang.Object.wait(Native Method)

• waiting on java.lang.ref.ReferenceQueue$Lock@3dd1b6dc
  at java.lang.ref.ReferenceQueue.remove(ReferenceQueue.java:135)
  at java.lang.ref.ReferenceQueue.remove(ReferenceQueue.java:151)
  at sun.java2d.Disposer.run(Disposer.java:145)
  at java.lang.Thread.run(Thread.java:745)

"Server Watchdog" Id=44 RUNNABLE
at sun.management.ThreadImpl.dumpThreads0(Native Method)
at sun.management.ThreadImpl.dumpAllThreads(ThreadImpl.java:446)
at lb.run(SourceFile:43)
at java.lang.Thread.run(Thread.java:745)

"Netty Epoll Server IO #1" Id=20 RUNNABLE (in native)
at io.netty.channel.epoll.Native.epollWait(Native Method)
at io.netty.channel.epoll.EpollEventLoop.epollWait(EpollEventLoop.java:194)
at io.netty.channel.epoll.EpollEventLoop.run(EpollEventLoop.java:219)
at io.netty.util.concurrent.SingleThreadEventExecutor$2.run(SingleThreadEventExecutor.java:116)
at java.lang.Thread.run(Thread.java:745)

"Netty Epoll Server IO #0" Id=19 RUNNABLE (in native)
at io.netty.channel.epoll.Native.epollWait(Native Method)
at io.netty.channel.epoll.EpollEventLoop.epollWait(EpollEventLoop.java:194)
at io.netty.channel.epoll.EpollEventLoop.run(EpollEventLoop.java:219)
at io.netty.util.concurrent.SingleThreadEventExecutor$2.run(SingleThreadEventExecutor.java:116)
at java.lang.Thread.run(Thread.java:745)

"Server console handler" Id=16 RUNNABLE (in native)
at java.io.FileInputStream.readBytes(Native Method)
at java.io.FileInputStream.read(FileInputStream.java:272)
at java.io.BufferedInputStream.read1(BufferedInputStream.java:273)
at java.io.BufferedInputStream.read(BufferedInputStream.java:334)

• locked java.io.BufferedInputStream@133c4539
  at sun.nio.cs.StreamDecoder.readBytes(StreamDecoder.java:283)
  at sun.nio.cs.StreamDecoder.implRead(StreamDecoder.java:325)
  at sun.nio.cs.StreamDecoder.read(StreamDecoder.java:177)
• locked java.io.InputStreamReader@3399ceef
  at java.io.InputStreamReader.read(InputStreamReader.java:184)
  ...

"DestroyJavaVM" Id=15 RUNNABLE

"Server thread" Id=13 RUNNABLE
at com.google.common.collect.AbstractIterator.hasNext(AbstractIterator.java:138)
at asb.a(SourceFile:738)
at ahp.a(SourceFile:2311)
at o.a(SourceFile:464)
at o.b(SourceFile:141)
at j.a(SourceFile:51)
at ahf.a(SourceFile:105)
at akg.b(SourceFile:101)
...

"Server Infinisleeper" Id=12 TIMED_WAITING
at java.lang.Thread.sleep(Native Method)
at la$1.run(SourceFile:77)

"Snooper Timer" Id=11 TIMED_WAITING on java.util.TaskQueue@36e0c760
at java.lang.Object.wait(Native Method)

• waiting on java.util.TaskQueue@36e0c760
  at java.util.TimerThread.mainLoop(Timer.java:552)
  at java.util.TimerThread.run(Timer.java:505)

"Signal Dispatcher" Id=5 RUNNABLE

"Finalizer" Id=3 WAITING on java.lang.ref.ReferenceQueue$Lock@5f418bc5
at java.lang.Object.wait(Native Method)

• waiting on java.lang.ref.ReferenceQueue$Lock@5f418bc5
  at java.lang.ref.ReferenceQueue.remove(ReferenceQueue.java:135)
  at java.lang.ref.ReferenceQueue.remove(ReferenceQueue.java:151)
  at java.lang.ref.Finalizer$FinalizerThread.run(Finalizer.java:209)

"Reference Handler" Id=2 WAITING on java.lang.ref.Reference$Lock@483f635e
at java.lang.Object.wait(Native Method)

• waiting on java.lang.ref.Reference$Lock@483f635e
  at java.lang.Object.wait(Object.java:503)
  at java.lang.ref.Reference$ReferenceHandler.run(Reference.java:133)

Stacktrace:
at lb.run(SourceFile:59)
at java.lang.Thread.run(Thread.java:745)

– System Details –
Details:
Minecraft Version: 16w02a
Operating System: Linux (amd64) version 2.6.32-431.29.2.el6.x86_64
Java Version: 1.7.0_65, Oracle Corporation
Java VM Version: OpenJDK 64-Bit Server VM (mixed mode), Oracle Corporation
Memory: 64115928 bytes (61 MB) / 129761280 bytes (123 MB) up to 1037959168 bytes (989 MB)
JVM Flags: 4 total; -XX:MaxPermSize=256M -XX:+UseConcMarkSweepGC -Xmx1024M -Xms128M
IntCache: cache: 0, tcache: 0, allocated: 0, tallocated: 0
Profiler Position: N/A (disabled)
Player Count: 1 / 25; [lr['alvin8t'/7, l='Lightwire', x=1016.59, y=41.17, z=997.11]]
Is Modded: Unknown (can't tell)
Type: Dedicated Server (map_server.txt)