Server randomly crashes and I don't know why

The server randomly crashed for no apparent reason after a server restart. Here is the crash log

Minecraft Crash Report ----
// You're mean.

Time: 1/4/19 10:22 PM
Description: Watching Server

java.lang.Error
at bbt$$Lambda$2166/610483916.apply(Unknown Source)
at java.util.stream.ReferencePipeline$3$1.accept(ReferencePipeline.java:193)
at java.util.Spliterators$IteratorSpliterator.tryAdvance(Spliterators.java:1812)
at java.util.stream.StreamSpliterators$WrappingSpliterator.lambda$initPartialTraversalState$0(StreamSpliterators.java:294)
at java.util.stream.StreamSpliterators$WrappingSpliterator$$Lambda$1866/607307371.getAsBoolean(Unknown Source)
at java.util.stream.StreamSpliterators$AbstractWrappingSpliterator.fillBuffer(StreamSpliterators.java:206)
at java.util.stream.StreamSpliterators$AbstractWrappingSpliterator.doAdvance(StreamSpliterators.java:161)
at java.util.stream.StreamSpliterators$WrappingSpliterator.tryAdvance(StreamSpliterators.java:300)
at java.util.stream.Streams$ConcatSpliterator.tryAdvance(Streams.java:728)
at java.util.stream.Streams$ConcatSpliterator.tryAdvance(Streams.java:728)
at java.util.Spliterators$1Adapter.hasNext(Spliterators.java:681)
at yy$1.tryAdvance(SourceFile:32)
at java.util.Spliterators$1Adapter.hasNext(Spliterators.java:681)
at cmu.a(SourceFile:182)
at agv.a(SourceFile:643)
at alx.a(SourceFile:128)
at ahe.k(SourceFile:2065)
at ahf.k(SourceFile:474)
at alx.k(SourceFile:152)
at ahe.W_(SourceFile:1886)
at ahf.W_(SourceFile:285)
at alz.W_(SourceFile:75)
at bbp.a(SourceFile:1167)
at uq.a(SourceFile:391)
at bbp.g(SourceFile:1147)
at bbp.m_(SourceFile:1029)
at uq.m_(SourceFile:307)
at net.minecraft.server.MinecraftServer.b(SourceFile:844)
at tr.b(SourceFile:337)
at net.minecraft.server.MinecraftServer.a(SourceFile:773)
at net.minecraft.server.MinecraftServer.run(SourceFile:639)
at java.lang.Thread.run(Thread.java:748)

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

– Head –
Thread: Server Watchdog
Stacktrace:
at bbt$$Lambda$2166/610483916.apply(Unknown Source)
at java.util.stream.ReferencePipeline$3$1.accept(ReferencePipeline.java:193)
at java.util.Spliterators$IteratorSpliterator.tryAdvance(Spliterators.java:1812)
at java.util.stream.StreamSpliterators$WrappingSpliterator.lambda$initPartialTraversalState$0(StreamSpliterators.java:294)
at java.util.stream.StreamSpliterators$WrappingSpliterator$$Lambda$1866/607307371.getAsBoolean(Unknown Source)
at java.util.stream.StreamSpliterators$AbstractWrappingSpliterator.fillBuffer(StreamSpliterators.java:206)
at java.util.stream.StreamSpliterators$AbstractWrappingSpliterator.doAdvance(StreamSpliterators.java:161)
at java.util.stream.StreamSpliterators$WrappingSpliterator.tryAdvance(StreamSpliterators.java:300)
at java.util.stream.Streams$ConcatSpliterator.tryAdvance(Streams.java:728)
at java.util.stream.Streams$ConcatSpliterator.tryAdvance(Streams.java:728)
at java.util.Spliterators$1Adapter.hasNext(Spliterators.java:681)
at yy$1.tryAdvance(SourceFile:32)
at java.util.Spliterators$1Adapter.hasNext(Spliterators.java:681)
at cmu.a(SourceFile:182)
at agv.a(SourceFile:643)
at alx.a(SourceFile:128)
at ahe.k(SourceFile:2065)
at ahf.k(SourceFile:474)
at alx.k(SourceFile:152)
at ahe.W_(SourceFile:1886)
at ahf.W_(SourceFile:285)
at alz.W_(SourceFile:75)
at bbp.a(SourceFile:1167)
at uq.a(SourceFile:391)
at bbp.g(SourceFile:1147)
at bbp.m_(SourceFile:1029)
at uq.m_(SourceFile:307)
at net.minecraft.server.MinecraftServer.b(SourceFile:844)
at tr.b(SourceFile:337)
at net.minecraft.server.MinecraftServer.a(SourceFile:773)

– Thread Dump –
Details:
Threads: "Keep-Alive-Timer" Id=1827 TIMED_WAITING
at java.lang.Thread.sleep(Native Method)
at sun.net.www.http.KeepAliveCache.run(KeepAliveCache.java:172)
at java.lang.Thread.run(Thread.java:748)

"Server Watchdog" Id=1815 RUNNABLE
at sun.management.ThreadImpl.dumpThreads0(Native Method)
at sun.management.ThreadImpl.dumpAllThreads(ThreadImpl.java:454)
at tu.run(SourceFile:45)
at java.lang.Thread.run(Thread.java:748)

"Query Listener #1" Id=1814 RUNNABLE
at java.net.PlainDatagramSocketImpl.receive0(Native Method)

• locked java.net.PlainDatagramSocketImpl@19edcdc8
  at java.net.AbstractPlainDatagramSocketImpl.receive(AbstractPlainDatagramSocketImpl.java:143)
  - locked java.net.PlainDatagramSocketImpl@19edcdc8
  at java.net.DatagramSocket.receive(DatagramSocket.java:812)
  - locked java.net.DatagramPacket@172a3085
  - locked java.net.DatagramSocket@3cbcba7
  at xi.run(SourceFile:260)
  at java.lang.Thread.run(Thread.java:748)

"Netty Epoll Server IO #1" Id=1803 RUNNABLE
at java.util.zip.Deflater.deflateBytes(Native Method)
at java.util.zip.Deflater.deflate(Deflater.java:444)

• locked java.util.zip.ZStreamRef@1315a6b8
  at java.util.zip.Deflater.deflate(Deflater.java:385)
  at iq.a(SourceFile:36)
  at iq.encode(SourceFile:9)
  at io.netty.handler.codec.MessageToByteEncoder.write(MessageToByteEncoder.java:107)
  at io.netty.channel.AbstractChannelHandlerContext.invokeWrite0(AbstractChannelHandlerContext.java:738)
  at io.netty.channel.AbstractChannelHandlerContext.invokeWrite(AbstractChannelHandlerContext.java:730)
  ...

"Server-Worker-1" Id=1802 TIMED_WAITING on java.util.concurrent.ForkJoinPool@56173abe
at sun.misc.Unsafe.park(Native Method)

• waiting on java.util.concurrent.ForkJoinPool@56173abe
  at java.util.concurrent.ForkJoinPool.awaitWork(ForkJoinPool.java:1824)
  at java.util.concurrent.ForkJoinPool.runWorker(ForkJoinPool.java:1693)
  at java.util.concurrent.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:157)

"Netty Epoll Server IO #0" Id=1801 RUNNABLE (in native)
at io.netty.channel.epoll.Native.epollWait0(Native Method)
at io.netty.channel.epoll.Native.epollWait(Native.java:114)
at io.netty.channel.epoll.EpollEventLoop.epollWait(EpollEventLoop.java:239)
at io.netty.channel.epoll.EpollEventLoop.run(EpollEventLoop.java:256)
at io.netty.util.concurrent.SingleThreadEventExecutor$5.run(SingleThreadEventExecutor.java:884)
at java.lang.Thread.run(Thread.java:748)

"ObjectCleanerThread" Id=1800 TIMED_WAITING on java.lang.ref.ReferenceQueue$Lock@21e32e39
at java.lang.Object.wait(Native Method)

• waiting on java.lang.ref.ReferenceQueue$Lock@21e32e39
  at java.lang.ref.ReferenceQueue.remove(ReferenceQueue.java:144)
  at io.netty.util.internal.ObjectCleaner$1.run(ObjectCleaner.java:54)
  at io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30)
  at java.lang.Thread.run(Thread.java:748)

"Server console handler" Id=1799 RUNNABLE (in native)
at java.io.FileInputStream.readBytes(Native Method)
at java.io.FileInputStream.read(FileInputStream.java:255)
at java.io.BufferedInputStream.read1(BufferedInputStream.java:284)
at java.io.BufferedInputStream.read(BufferedInputStream.java:345)

• locked java.io.BufferedInputStream@678b8c98
  at sun.nio.cs.StreamDecoder.readBytes(StreamDecoder.java:284)
  at sun.nio.cs.StreamDecoder.implRead(StreamDecoder.java:326)
  at sun.nio.cs.StreamDecoder.read(StreamDecoder.java:178)
  - locked java.io.InputStreamReader@5995c6b7
  at java.io.InputStreamReader.read(InputStreamReader.java:184)
  ...

"DestroyJavaVM" Id=1798 RUNNABLE

"Server thread" Id=1795 RUNNABLE
at bbt$$Lambda$2166/610483916.apply(Unknown Source)
at java.util.stream.ReferencePipeline$3$1.accept(ReferencePipeline.java:193)
at java.util.Spliterators$IteratorSpliterator.tryAdvance(Spliterators.java:1812)
at java.util.stream.StreamSpliterators$WrappingSpliterator.lambda$initPartialTraversalState$0(StreamSpliterators.java:294)
at java.util.stream.StreamSpliterators$WrappingSpliterator$$Lambda$1866/607307371.getAsBoolean(Unknown Source)
at java.util.stream.StreamSpliterators$AbstractWrappingSpliterator.fillBuffer(StreamSpliterators.java:206)
at java.util.stream.StreamSpliterators$AbstractWrappingSpliterator.doAdvance(StreamSpliterators.java:161)
at java.util.stream.StreamSpliterators$WrappingSpliterator.tryAdvance(StreamSpliterators.java:300)
...

"Server Infinisleeper" Id=1796 TIMED_WAITING
at java.lang.Thread.sleep(Native Method)
at tr$1.run(SourceFile:91)

"Snooper Timer" Id=1794 WAITING on java.util.TaskQueue@3638c5f1
at java.lang.Object.wait(Native Method)

• waiting on java.util.TaskQueue@3638c5f1
  at java.lang.Object.wait(Object.java:502)
  at java.util.TimerThread.mainLoop(Timer.java:526)
  at java.util.TimerThread.run(Timer.java:505)

"Signal Dispatcher" Id=4 RUNNABLE

"Finalizer" Id=3 WAITING on java.lang.ref.ReferenceQueue$Lock@e12b7e9
at java.lang.Object.wait(Native Method)

• waiting on java.lang.ref.ReferenceQueue$Lock@e12b7e9
  at java.lang.ref.ReferenceQueue.remove(ReferenceQueue.java:144)
  at java.lang.ref.ReferenceQueue.remove(ReferenceQueue.java:165)
  at java.lang.ref.Finalizer$FinalizerThread.run(Finalizer.java:216)

"Reference Handler" Id=2 WAITING on java.lang.ref.Reference$Lock@35c605ff
at java.lang.Object.wait(Native Method)

• waiting on java.lang.ref.Reference$Lock@35c605ff
  at java.lang.Object.wait(Object.java:502)
  at java.lang.ref.Reference.tryHandlePending(Reference.java:191)
  at java.lang.ref.Reference$ReferenceHandler.run(Reference.java:153)

Stacktrace:
at tu.run(SourceFile:61)
at java.lang.Thread.run(Thread.java:748)

– System Details –
Details:
Minecraft Version: 18w50a
Operating System: Linux (amd64) version 4.15.0-43-generic
Java Version: 1.8.0_181, Oracle Corporation
Java VM Version: OpenJDK 64-Bit Server VM (mixed mode), Oracle Corporation
Memory: 405298200 bytes (386 MB) / 1377071104 bytes (1313 MB) up to 4151836672 bytes (3959 MB)
JVM Flags: 2 total; -Xms128M -Xmx4096M
Player Count: 3 / 50; [us['XPownage'/195, l='world', x=-295.86, y=64.00, z=-135.49], us['rollrosenYT'/928, l='world', x=-861.50, y=63.00, z=445.50], us['Athena8pie'/929, l='world', x=-292.30, y=64.00, z=-143.86]]
Data Packs: vanilla
Is Modded: Unknown (can't tell)
Type: Dedicated Server (map_server.txt)