I had the same issue. I debugged it and found it to be caused by what I assume is a version mismatch between class net.minecraftforge.fml.common.network.NetworkRegistry and enum net.minecraftforge.fml.relauncher.Side.
Side has 3 values but the NetworkRegistry code appears to assume there are only 2, CLIENT and SERVER.
I fixed this by taking a copy of the NetworkRegistry class, and editing it as follows:
In the private, parameterless constructor, add the following line:
channels.put(Side.BUKKIT, Maps.<String,FMLEmbeddedChannel>newConcurrentMap());
Code change
Then you just need to make sure that your version of the class in on the classpath before the original version (if you're using eclipse then it will be automatically). You also need to make sure that you use the exact same package name for your version of the class.
Answer from winstar on Stack OverflowVideos
when people try to connect to my server, they receive this error messageinternal exception java.lang.nullpointerexception can not invoke "net.minecraft.nbt.compoundtag.m_128459_(string)
i also received this error message as well but during this test for some reason it let me join the server, i've tested this out on singleplayer as well and the world works fine nothing seems to be corrupted it just doesn't work for the server.
we've also made multiple worlds for this specific pack i've made and they all have had this problem, randomly sometimes people will be able to join and play normally but other times they get this error and they cant play.
friends latest.log: https://mclo.gs/mHmks83
servers lastest.log: https://mclo.gs/si9AJk2
I'm using Minecraft Forge, and the game freezes when I try to play a singleplayer world.
Part of the log where it freezes (not the entire thing because has 52000+ infos):
17:25:34.375
game
at appeng.core.AppEng.serverStopped(AppEng.java:218) 17:25:34.375 game
at appeng.core.AppEng$$Lambda$42439/1674748790.accept(Unknown Source) 17:25:34.375 game
at net.minecraftforge.eventbus.EventBus.doCastFilter(EventBus.java:247) 17:25:34.375 game
at net.minecraftforge.eventbus.EventBus.lambda$addListener$11(EventBus.java:239) 17:25:34.375 game
at net.minecraftforge.eventbus.EventBus$$Lambda$3053/743588298.invoke(Unknown Source) 17:25:34.375 game
at net.minecraftforge.eventbus.EventBus$$Lambda$4178/1865052252.invoke(Unknown Source) 17:25:34.375 game
at net.minecraftforge.eventbus.EventBus.post(EventBus.java:302) 17:25:34.375 game
at net.minecraftforge.eventbus.EventBus.post(EventBus.java:283) 17:25:34.375 game
at net.minecraftforge.fml.server.ServerLifecycleHooks.handleServerStopped(ServerLifecycleHooks.java:124) 17:25:34.375 game
at net.minecraft.server.MinecraftServer.func_240802_v_(MinecraftServer.java:683) 17:25:34.375 game
at net.minecraft.server.MinecraftServer.func_240783_a_(MinecraftServer.java:232) 17:25:34.375 game
at net.minecraft.server.MinecraftServer$$Lambda$79982/1441080155.run(Unknown Source) 17:25:34.375 game
at java.lang.Thread.run(Thread.java:745) 17:25:34.375 game
17:25:34.375
game
[17:25:34] [Server thread/ERROR] [minecraft/MinecraftServer]: java.lang.NullPointerException
It freezes at java.lang.nullpointerexception. Why does it freeze there when i try to load into a singleplayer world?
Your problem is already fixed probably, but for the people who are searching for a fix, follow my steps
- Search for CMD and run it as administrator
- Type in the bar:
netsh winsock reset - It should be fixed!
- If it still doesn't work, try contacting Mojang, the creators of Minecraft
If you are playing newer snapshots, This was a recent bug in the 17w14-16
They seem to have finally fixed it in 17w17a/b
It seemed to be related to a number of new additions like advancements and parrots.
Update your server_jar and your minecraft client to 17w17b (current)
If you are getting this issue on 1.11.2 release. Then open a bug report at bugs.mojang.com