This is what my Server Log says.

24.05 10:55:34 [Server] Server thread/ERROR Encountered an unexpected exception 24.05 10:55:34 [Server] INFO h: Exception generating new chunk 24.05 10:55:34 [Server] INFO at net.minecraft.server.MinecraftServer.w(SourceFile:698) ~[sserver.jar:?] 24.05 10:55:34 [Server] INFO at rv.w(SourceFile:365) ~[sserver.jar:?] 24.05 10:55:34 [Server] INFO at net.minecraft.server.MinecraftServer.v(SourceFile:627) ~[sserver.jar:?] 24.05 10:55:34 [Server] INFO at net.minecraft.server.MinecraftServer.run(SourceFile:532) [sserver.jar:?] 24.05 10:55:34 [Server] INFO at java.lang.Thread.run(Thread.java:745) [?:1.8.0_111] 24.05 10:55:34 [Server] INFO Caused by: java.util.concurrent.ExecutionException: java.lang.OutOfMemoryError: Java heap space 24.05 10:55:34 [Server] INFO at java.util.concurrent.CompletableFuture.reportGet(CompletableFuture.java:357) ~[?:1.8.0_111] 24.05 10:55:34 [Server] INFO at java.util.concurrent.CompletableFuture.get(CompletableFuture.java:1895) ~[?:1.8.0_111] 24.05 10:55:34 [Server] INFO at sj.c(SourceFile:129) ~[sserver.jar:?] 24.05 10:55:34 [Server] INFO at sr.a(SourceFile:84) ~[sserver.jar:?] 24.05 10:55:34 [Server] INFO at ss.c(SourceFile:143) ~[sserver.jar:?] 24.05 10:55:34 [Server] INFO at sk.i_(SourceFile:223) ~[sserver.jar:?] 24.05 10:55:34 [Server] INFO at net.minecraft.server.MinecraftServer.w(SourceFile:694) ~[sserver.jar:?] 24.05 10:55:34 [Server] INFO ... 4 more 24.05 10:55:34 [Server] INFO Caused by: java.lang.OutOfMemoryError: Java heap space 24.05 10:55:34 [Server] INFO at it.unimi.dsi.fastutil.ints.IntArrayFIFOQueue.resize(IntArrayFIFOQueue.java:175) ~[sserver.jar:?] 24.05 10:55:34 [Server] INFO at it.unimi.dsi.fastutil.ints.IntArrayFIFOQueue.expand(IntArrayFIFOQueue.java:189) ~[sserver.jar:?] 24.05 10:55:34 [Server] INFO at it.unimi.dsi.fastutil.ints.IntArrayFIFOQueue.enqueue(IntArrayFIFOQueue.java:201) ~[sserver.jar:?] 24.05 10:55:34 [Server] INFO at cbm.a(SourceFile:142) ~[sserver.jar:?] 24.05 10:55:34 [Server] INFO at cbm.a(SourceFile:146) ~[sserver.jar:?] 24.05 10:55:34 [Server] INFO at cbm.a(SourceFile:130) ~[sserver.jar:?] 24.05 10:55:34 [Server] INFO at cbp.a(SourceFile:62) ~[sserver.jar:?] 24.05 10:55:34 [Server] INFO at tb.a(SourceFile:23) ~[sserver.jar:?] 24.05 10:55:34 [Server] INFO at sx.a(SourceFile:34) ~[sserver.jar:?] 24.05 10:55:34 [Server] INFO at bqc.a(SourceFile:87) ~[sserver.jar:?] 24.05 10:55:34 [Server] INFO at td.a(SourceFile:59) ~[sserver.jar:?] 24.05 10:55:34 [Server] INFO at td.a(SourceFile:23) ~[sserver.jar:?] 24.05 10:55:34 [Server] INFO at agg$a.a(SourceFile:143) ~[sserver.jar:?] 24.05 10:55:35 [Multicraft] Server shut down (running) 24.05 10:55:35 [Multicraft] Restarting crashed server in 5 seconds 24.05 10:55:35 [Multicraft] Server stopped