There are some areas where server crashes while trying to load chunks from world which is freshly converted to Anvil format.
The same area on vanilla 1.12.2 server seems to be working just fine.
Crash log:
[16:39:36 ERROR]: The server has stopped responding! [16:39:36 ERROR]: Please report this to http://www.spigotmc.org/ [16:39:36 ERROR]: Be sure to include ALL relevant console errors and Minecraft crash reports [16:39:36 ERROR]: Spigot version: git-Spigot-e8ded36-acbc348 (MC: 1.12.2) [16:39:36 ERROR]: ------------------------------ [16:39:36 ERROR]: Server thread dump (Look for plugins here before reporting to Spigot!): [16:39:36 ERROR]: ------------------------------ [16:39:36 ERROR]: Current Thread: Server thread [16:39:36 ERROR]: PID: 17 | Suspended: false | Native: false | State: RUNNABLE [16:39:36 ERROR]: Stack: [16:39:36 ERROR]: net.minecraft.server.v1_12_R1.World.isValidLocation(World.java:262) [16:39:36 ERROR]: net.minecraft.server.v1_12_R1.World.getBrightness(World.java:762) [16:39:36 ERROR]: net.minecraft.server.v1_12_R1.World.c(World.java:2366) [16:39:36 ERROR]: net.minecraft.server.v1_12_R1.Chunk.a(Chunk.java:284) [16:39:36 ERROR]: net.minecraft.server.v1_12_R1.Chunk.b(Chunk.java:274) [16:39:36 ERROR]: net.minecraft.server.v1_12_R1.Chunk.h(Chunk.java:253) [16:39:36 ERROR]: net.minecraft.server.v1_12_R1.Chunk.z(Chunk.java:1206) [16:39:36 ERROR]: net.minecraft.server.v1_12_R1.Chunk.o(Chunk.java:1192) [16:39:36 ERROR]: net.minecraft.server.v1_12_R1.Chunk.b(Chunk.java:1029) [16:39:36 ERROR]: net.minecraft.server.v1_12_R1.WorldServer.j(WorldServer.java:485) [16:39:36 ERROR]: net.minecraft.server.v1_12_R1.WorldServer.doTick(WorldServer.java:316) [16:39:36 ERROR]: net.minecraft.server.v1_12_R1.MinecraftServer.D(MinecraftServer.java:801) [16:39:36 ERROR]: net.minecraft.server.v1_12_R1.DedicatedServer.D(DedicatedServer.java:406) [16:39:36 ERROR]: net.minecraft.server.v1_12_R1.MinecraftServer.C(MinecraftServer.java:679) [16:39:36 ERROR]: net.minecraft.server.v1_12_R1.MinecraftServer.run(MinecraftServer.java:577) [16:39:36 ERROR]: java.lang.Thread.run(Thread.java:748) [16:39:36 ERROR]: ------------------------------ [16:39:36 ERROR]: Entire Thread Dump: [16:39:36 ERROR]: ------------------------------ [16:39:36 ERROR]: Current Thread: process reaper [16:39:36 ERROR]: PID: 58 | Suspended: false | Native: false | State: RUNNABLE [16:39:36 ERROR]: Stack: [16:39:36 ERROR]: java.lang.UNIXProcess.waitForProcessExit(Native Method) [16:39:36 ERROR]: java.lang.UNIXProcess.lambda$initStreams$3(UNIXProcess.java:289) [16:39:36 ERROR]: java.lang.UNIXProcess$$Lambda$7/1851691492.run(Unknown Source) [16:39:36 ERROR]: java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) [16:39:36 ERROR]: java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) [16:39:36 ERROR]: java.lang.Thread.run(Thread.java:748) [16:39:36 ERROR]: ------------------------------ [16:39:36 ERROR]: Current Thread: Async Chat Thread - #0 [16:39:36 ERROR]: PID: 57 | Suspended: false | Native: false | State: TIMED_WAITING [16:39:36 ERROR]: Stack: [16:39:36 ERROR]: sun.misc.Unsafe.park(Native Method) [16:39:36 ERROR]: java.util.concurrent.locks.LockSupport.parkNanos(LockSupport.java:215) [16:39:36 ERROR]: java.util.concurrent.SynchronousQueue$TransferStack.awaitFulfill(SynchronousQueue.java:460) [16:39:36 ERROR]: java.util.concurrent.SynchronousQueue$TransferStack.transfer(SynchronousQueue.java:362) [16:39:36 ERROR]: java.util.concurrent.SynchronousQueue.poll(SynchronousQueue.java:941) [16:39:36 ERROR]: java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:1073) [16:39:36 ERROR]: java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1134) [16:39:36 ERROR]: java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) [16:39:36 ERROR]: java.lang.Thread.run(Thread.java:748) [16:39:36 ERROR]: ------------------------------ [16:39:36 ERROR]: Current Thread: Chunk I/O Executor Thread-1 [16:39:36 ERROR]: PID: 52 | Suspended: false | Native: false | State: WAITING [16:39:36 ERROR]: Stack: [16:39:36 ERROR]: sun.misc.Unsafe.park(Native Method) [16:39:36 ERROR]: java.util.concurrent.locks.LockSupport.park(LockSupport.java:175) [16:39:36 ERROR]: java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.await(AbstractQueuedSynchronizer.java:2039) [16:39:36 ERROR]: java.util.concurrent.LinkedBlockingQueue.take(LinkedBlockingQueue.java:442) [16:39:36 ERROR]: java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:1074) [16:39:36 ERROR]: java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1134) [16:39:36 ERROR]: java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) [16:39:36 ERROR]: java.lang.Thread.run(Thread.java:748) [16:39:36 ERROR]: ------------------------------ [16:39:36 ERROR]: Current Thread: Netty Epoll Server IO #1 [16:39:36 ERROR]: PID: 46 | Suspended: false | Native: true | State: RUNNABLE [16:39:36 ERROR]: Stack: [16:39:36 ERROR]: io.netty.channel.epoll.Native.epollWait0(Native Method) [16:39:36 ERROR]: io.netty.channel.epoll.Native.epollWait(Native.java:114) [16:39:36 ERROR]: io.netty.channel.epoll.EpollEventLoop.epollWait(EpollEventLoop.java:235) [16:39:36 ERROR]: io.netty.channel.epoll.EpollEventLoop.run(EpollEventLoop.java:252) [16:39:36 ERROR]: io.netty.util.concurrent.SingleThreadEventExecutor$5.run(SingleThreadEventExecutor.java:884) [16:39:36 ERROR]: java.lang.Thread.run(Thread.java:748) [16:39:36 ERROR]: ------------------------------ [16:39:36 ERROR]: Current Thread: File IO Thread [16:39:36 ERROR]: PID: 38 | Suspended: false | Native: false | State: TIMED_WAITING [16:39:36 ERROR]: Stack: [16:39:36 ERROR]: java.lang.Thread.sleep(Native Method) [16:39:36 ERROR]: net.minecraft.server.v1_12_R1.FileIOThread.c(SourceFile:51) [16:39:36 ERROR]: net.minecraft.server.v1_12_R1.FileIOThread.run(SourceFile:30) [16:39:36 ERROR]: java.lang.Thread.run(Thread.java:748) [16:39:36 ERROR]: ------------------------------ [16:39:36 ERROR]: Current Thread: Timer-2 [16:39:36 ERROR]: PID: 29 | Suspended: false | Native: false | State: TIMED_WAITING [16:39:36 ERROR]: Stack: [16:39:36 ERROR]: java.lang.Object.wait(Native Method) [16:39:36 ERROR]: java.util.TimerThread.mainLoop(Timer.java:552) [16:39:36 ERROR]: java.util.TimerThread.run(Timer.java:505) [16:39:36 ERROR]: ------------------------------ [16:39:36 ERROR]: Current Thread: Abandoned connection cleanup thread [16:39:36 ERROR]: PID: 28 | Suspended: false | Native: false | State: TIMED_WAITING [16:39:36 ERROR]: Stack: [16:39:36 ERROR]: java.lang.Object.wait(Native Method) [16:39:36 ERROR]: java.lang.ref.ReferenceQueue.remove(ReferenceQueue.java:144) [16:39:36 ERROR]: com.mysql.jdbc.AbandonedConnectionCleanupThread.run(AbandonedConnectionCleanupThread.java:64) [16:39:36 ERROR]: java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) [16:39:36 ERROR]: java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) [16:39:36 ERROR]: java.lang.Thread.run(Thread.java:748) [16:39:36 ERROR]: ------------------------------ [16:39:36 ERROR]: Current Thread: Timer-1 [16:39:36 ERROR]: PID: 27 | Suspended: false | Native: false | State: TIMED_WAITING [16:39:36 ERROR]: Stack: [16:39:36 ERROR]: java.lang.Object.wait(Native Method) [16:39:36 ERROR]: java.util.TimerThread.mainLoop(Timer.java:552) [16:39:36 ERROR]: java.util.TimerThread.run(Timer.java:505) [16:39:36 ERROR]: ------------------------------ [16:39:36 ERROR]: Current Thread: Timer-0 [16:39:36 ERROR]: PID: 26 | Suspended: false | Native: false | State: TIMED_WAITING [16:39:36 ERROR]: Stack: [16:39:36 ERROR]: java.lang.Object.wait(Native Method) [16:39:36 ERROR]: java.util.TimerThread.mainLoop(Timer.java:552) [16:39:36 ERROR]: java.util.TimerThread.run(Timer.java:505) [16:39:36 ERROR]: ------------------------------ [16:39:36 ERROR]: Current Thread: Netty Epoll Server IO #0 [16:39:36 ERROR]: PID: 25 | Suspended: false | Native: true | State: RUNNABLE [16:39:36 ERROR]: Stack: [16:39:36 ERROR]: io.netty.channel.epoll.Native.epollWait0(Native Method) [16:39:36 ERROR]: io.netty.channel.epoll.Native.epollWait(Native.java:114) [16:39:36 ERROR]: io.netty.channel.epoll.EpollEventLoop.epollWait(EpollEventLoop.java:235) [16:39:36 ERROR]: io.netty.channel.epoll.EpollEventLoop.run(EpollEventLoop.java:252) [16:39:36 ERROR]: io.netty.util.concurrent.SingleThreadEventExecutor$5.run(SingleThreadEventExecutor.java:884) [16:39:36 ERROR]: java.lang.Thread.run(Thread.java:748) [16:39:36 ERROR]: ------------------------------ [16:39:36 ERROR]: Current Thread: ObjectCleanerThread [16:39:36 ERROR]: PID: 24 | Suspended: false | Native: false | State: TIMED_WAITING [16:39:36 ERROR]: Stack: [16:39:36 ERROR]: java.lang.Object.wait(Native Method) [16:39:36 ERROR]: java.lang.ref.ReferenceQueue.remove(ReferenceQueue.java:144) [16:39:36 ERROR]: io.netty.util.internal.ObjectCleaner$1.run(ObjectCleaner.java:54) [16:39:36 ERROR]: io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30) [16:39:36 ERROR]: java.lang.Thread.run(Thread.java:748) [16:39:36 ERROR]: ------------------------------ [16:39:36 ERROR]: Current Thread: Spigot Metrics Thread [16:39:36 ERROR]: PID: 23 | Suspended: false | Native: false | State: TIMED_WAITING [16:39:36 ERROR]: Stack: [16:39:36 ERROR]: java.lang.Object.wait(Native Method) [16:39:36 ERROR]: java.util.TimerThread.mainLoop(Timer.java:552) [16:39:36 ERROR]: java.util.TimerThread.run(Timer.java:505) [16:39:36 ERROR]: ------------------------------ [16:39:36 ERROR]: Current Thread: Spigot Watchdog Thread [16:39:36 ERROR]: PID: 22 | Suspended: false | Native: false | State: RUNNABLE [16:39:36 ERROR]: Stack: [16:39:36 ERROR]: sun.management.ThreadImpl.dumpThreads0(Native Method) [16:39:36 ERROR]: sun.management.ThreadImpl.dumpAllThreads(ThreadImpl.java:454) [16:39:36 ERROR]: org.spigotmc.WatchdogThread.run(WatchdogThread.java:76) [16:39:36 ERROR]: ------------------------------ [16:39:36 ERROR]: Current Thread: Server console handler [16:39:36 ERROR]: PID: 20 | Suspended: false | Native: true | State: RUNNABLE [16:39:36 ERROR]: Thread is waiting on monitor(s): [16:39:36 ERROR]: Locked on:java.io.BufferedInputStream.read(BufferedInputStream.java:265) [16:39:36 ERROR]: Locked on:org.bukkit.craftbukkit.libs.jline.internal.NonBlockingInputStream.read(NonBlockingInputStream.java:169) [16:39:36 ERROR]: Locked on:org.bukkit.craftbukkit.libs.jline.internal.InputStreamReader.read(InputStreamReader.java:261) [16:39:36 ERROR]: Locked on:org.bukkit.craftbukkit.libs.jline.internal.InputStreamReader.read(InputStreamReader.java:198) [16:39:36 ERROR]: Stack: [16:39:36 ERROR]: java.io.FileInputStream.readBytes(Native Method) [16:39:36 ERROR]: java.io.FileInputStream.read(FileInputStream.java:255) [16:39:36 ERROR]: java.io.BufferedInputStream.fill(BufferedInputStream.java:246) [16:39:36 ERROR]: java.io.BufferedInputStream.read(BufferedInputStream.java:265) [16:39:36 ERROR]: org.bukkit.craftbukkit.libs.jline.internal.NonBlockingInputStream.read(NonBlockingInputStream.java:169) [16:39:36 ERROR]: org.bukkit.craftbukkit.libs.jline.internal.NonBlockingInputStream.read(NonBlockingInputStream.java:137) [16:39:36 ERROR]: org.bukkit.craftbukkit.libs.jline.internal.NonBlockingInputStream.read(NonBlockingInputStream.java:246) [16:39:36 ERROR]: org.bukkit.craftbukkit.libs.jline.internal.InputStreamReader.read(InputStreamReader.java:261) [16:39:36 ERROR]: org.bukkit.craftbukkit.libs.jline.internal.InputStreamReader.read(InputStreamReader.java:198) [16:39:36 ERROR]: org.bukkit.craftbukkit.libs.jline.console.ConsoleReader.readCharacter(ConsoleReader.java:2145) [16:39:36 ERROR]: org.bukkit.craftbukkit.libs.jline.console.ConsoleReader.readLine(ConsoleReader.java:2349) [16:39:36 ERROR]: net.minecraft.server.v1_12_R1.DedicatedServer$2.run(DedicatedServer.java:85) [16:39:36 ERROR]: ------------------------------ [16:39:36 ERROR]: Current Thread: Thread-4 [16:39:36 ERROR]: PID: 21 | Suspended: false | Native: false | State: RUNNABLE [16:39:36 ERROR]: Thread is waiting on monitor(s): [16:39:36 ERROR]: Locked on:java.io.BufferedInputStream.read(BufferedInputStream.java:265) [16:39:36 ERROR]: Stack: [16:39:36 ERROR]: java.io.FileInputStream.readBytes(Native Method) [16:39:36 ERROR]: java.io.FileInputStream.read(FileInputStream.java:255) [16:39:36 ERROR]: java.io.BufferedInputStream.fill(BufferedInputStream.java:246) [16:39:36 ERROR]: java.io.BufferedInputStream.read(BufferedInputStream.java:265) [16:39:36 ERROR]: org.bukkit.craftbukkit.libs.jline.internal.TerminalLineSettings.exec(TerminalLineSettings.java:204) [16:39:36 ERROR]: org.bukkit.craftbukkit.libs.jline.internal.TerminalLineSettings.exec(TerminalLineSettings.java:186) [16:39:36 ERROR]: org.bukkit.craftbukkit.libs.jline.internal.TerminalLineSettings.stty(TerminalLineSettings.java:181) [16:39:36 ERROR]: org.bukkit.craftbukkit.libs.jline.internal.TerminalLineSettings.get(TerminalLineSettings.java:74) [16:39:36 ERROR]: org.bukkit.craftbukkit.libs.jline.internal.TerminalLineSettings.getProperty(TerminalLineSettings.java:95) [16:39:36 ERROR]: org.bukkit.craftbukkit.libs.jline.UnixTerminal.getWidth(UnixTerminal.java:76) [16:39:36 ERROR]: org.bukkit.craftbukkit.libs.jline.console.ConsoleReader.drawBuffer(ConsoleReader.java:879) [16:39:36 ERROR]: org.bukkit.craftbukkit.libs.jline.console.ConsoleReader.drawBuffer(ConsoleReader.java:898) [16:39:36 ERROR]: org.bukkit.craftbukkit.libs.jline.console.ConsoleReader.drawLine(ConsoleReader.java:608) [16:39:36 ERROR]: org.bukkit.craftbukkit.v1_12_R1.util.TerminalConsoleWriterThread.run(TerminalConsoleWriterThread.java:40) [16:39:36 ERROR]: java.lang.Thread.run(Thread.java:748) [16:39:36 ERROR]: ------------------------------ [16:39:36 ERROR]: Current Thread: DestroyJavaVM [16:39:36 ERROR]: PID: 19 | Suspended: false | Native: false | State: RUNNABLE [16:39:36 ERROR]: Stack: [16:39:36 ERROR]: ------------------------------ [16:39:36 ERROR]: Current Thread: Server thread [16:39:36 ERROR]: PID: 17 | Suspended: false | Native: false | State: RUNNABLE [16:39:36 ERROR]: Stack: [16:39:36 ERROR]: net.minecraft.server.v1_12_R1.World.a(World.java:278) [16:39:36 ERROR]: net.minecraft.server.v1_12_R1.World.isLoaded(World.java:274) [16:39:36 ERROR]: net.minecraft.server.v1_12_R1.World.getBrightness(World.java:764) [16:39:36 ERROR]: net.minecraft.server.v1_12_R1.World.a(World.java:2262) [16:39:36 ERROR]: net.minecraft.server.v1_12_R1.World.c(World.java:2368) [16:39:36 ERROR]: net.minecraft.server.v1_12_R1.Chunk.a(Chunk.java:284) [16:39:36 ERROR]: net.minecraft.server.v1_12_R1.Chunk.b(Chunk.java:274) [16:39:36 ERROR]: net.minecraft.server.v1_12_R1.Chunk.h(Chunk.java:253) [16:39:36 ERROR]: net.minecraft.server.v1_12_R1.Chunk.z(Chunk.java:1206) [16:39:36 ERROR]: net.minecraft.server.v1_12_R1.Chunk.o(Chunk.java:1192) [16:39:36 ERROR]: net.minecraft.server.v1_12_R1.Chunk.b(Chunk.java:1029) [16:39:36 ERROR]: net.minecraft.server.v1_12_R1.WorldServer.j(WorldServer.java:485) [16:39:36 ERROR]: net.minecraft.server.v1_12_R1.WorldServer.doTick(WorldServer.java:316) [16:39:36 ERROR]: net.minecraft.server.v1_12_R1.MinecraftServer.D(MinecraftServer.java:801) [16:39:36 ERROR]: net.minecraft.server.v1_12_R1.DedicatedServer.D(DedicatedServer.java:406) [16:39:36 ERROR]: net.minecraft.server.v1_12_R1.MinecraftServer.C(MinecraftServer.java:679) [16:39:36 ERROR]: net.minecraft.server.v1_12_R1.MinecraftServer.run(MinecraftServer.java:577) [16:39:36 ERROR]: java.lang.Thread.run(Thread.java:748) [16:39:36 ERROR]: ------------------------------ [16:39:36 ERROR]: Current Thread: Server Infinisleeper [16:39:36 ERROR]: PID: 18 | Suspended: false | Native: false | State: TIMED_WAITING [16:39:36 ERROR]: Stack: [16:39:36 ERROR]: java.lang.Thread.sleep(Native Method) [16:39:36 ERROR]: net.minecraft.server.v1_12_R1.DedicatedServer$1.run(DedicatedServer.java:60) [16:39:36 ERROR]: ------------------------------ [16:39:36 ERROR]: Current Thread: NonBlockingInputStreamThread [16:39:36 ERROR]: PID: 15 | Suspended: false | Native: false | State: WAITING [16:39:36 ERROR]: Stack: [16:39:36 ERROR]: java.lang.Object.wait(Native Method) [16:39:36 ERROR]: org.bukkit.craftbukkit.libs.jline.internal.NonBlockingInputStream.run(NonBlockingInputStream.java:278) [16:39:36 ERROR]: java.lang.Thread.run(Thread.java:748) [16:39:36 ERROR]: ------------------------------ [16:39:36 ERROR]: Current Thread: Snooper Timer [16:39:36 ERROR]: PID: 13 | Suspended: false | Native: false | State: TIMED_WAITING [16:39:36 ERROR]: Stack: [16:39:36 ERROR]: java.lang.Object.wait(Native Method) [16:39:36 ERROR]: java.util.TimerThread.mainLoop(Timer.java:552) [16:39:36 ERROR]: java.util.TimerThread.run(Timer.java:505) [16:39:36 ERROR]: ------------------------------ [16:39:36 ERROR]: Current Thread: Signal Dispatcher [16:39:36 ERROR]: PID: 4 | Suspended: false | Native: false | State: RUNNABLE [16:39:36 ERROR]: Stack: [16:39:36 ERROR]: ------------------------------ [16:39:36 ERROR]: Current Thread: Finalizer [16:39:36 ERROR]: PID: 3 | Suspended: false | Native: false | State: WAITING [16:39:36 ERROR]: Stack: [16:39:36 ERROR]: java.lang.Object.wait(Native Method) [16:39:36 ERROR]: java.lang.ref.ReferenceQueue.remove(ReferenceQueue.java:144) [16:39:36 ERROR]: java.lang.ref.ReferenceQueue.remove(ReferenceQueue.java:165) [16:39:36 ERROR]: java.lang.ref.Finalizer$FinalizerThread.run(Finalizer.java:216) [16:39:36 ERROR]: ------------------------------ [16:39:36 ERROR]: Current Thread: Reference Handler [16:39:36 ERROR]: PID: 2 | Suspended: false | Native: false | State: WAITING [16:39:36 ERROR]: Stack: [16:39:36 ERROR]: java.lang.Object.wait(Native Method) [16:39:36 ERROR]: java.lang.Object.wait(Object.java:502) [16:39:36 ERROR]: java.lang.ref.Reference.tryHandlePending(Reference.java:191) [16:39:36 ERROR]: java.lang.ref.Reference$ReferenceHandler.run(Reference.java:153) [16:39:36 ERROR]: ------------------------------