[1.7.10] Running two Forge Instances from Eclipse

[jamioflan]

My teams mod requires a lot of testing with multiple players, and in the past I've just run two copies from Eclipse and connected using the "Open to LAN" features.

 

The first problem I had with 1.7.10 was that everyone was called "ForgeDevName", and so could not play LAN together. So I set up some custom launch configurations that use the program argument "--username jamioflan" or "--username Notch" and ran two different copies. Now when I connect I get the following error on the connecting client

 

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

---------------------------------------------------------------------------------------

 

-- Head --

Stacktrace:

at com.mojang.util.UUIDTypeAdapter.fromUUID(UUIDTypeAdapter.java:22)

at com.mojang.util.UUIDTypeAdapter.write(UUIDTypeAdapter.java:13)

at com.mojang.util.UUIDTypeAdapter.write(UUIDTypeAdapter.java:10)

at com.google.gson.internal.bind.TypeAdapterRuntimeTypeWrapper.write(TypeAdapterRuntimeTypeWrapper.java:68)

at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$1.write(ReflectiveTypeAdapterFactory.java:89)

at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$Adapter.write(ReflectiveTypeAdapterFactory.java:195)

at com.google.gson.Gson.toJson(Gson.java:593)

at com.google.gson.Gson.toJson(Gson.java:572)

at com.google.gson.Gson.toJson(Gson.java:527)

at com.google.gson.Gson.toJson(Gson.java:507)

at com.mojang.authlib.yggdrasil.YggdrasilAuthenticationService.makeRequest(YggdrasilAuthenticationService.java:54)

at com.mojang.authlib.yggdrasil.YggdrasilMinecraftSessionService.joinServer(YggdrasilMinecraftSessionService.java:76)

at net.minecraft.client.network.NetHandlerLoginClient.handleEncryptionRequest(NetHandlerLoginClient.java:62)

at net.minecraft.network.login.server.S01PacketEncryptionRequest.processPacket(S01PacketEncryptionRequest.java:54)

at net.minecraft.network.login.server.S01PacketEncryptionRequest.processPacket(S01PacketEncryptionRequest.java:62)

at net.minecraft.network.NetworkManager.processReceivedPackets(NetworkManager.java:247)

at net.minecraft.client.multiplayer.GuiConnecting.updateScreen(GuiConnecting.java:116)

 

-- Affected screen --

Details:

Screen name: net.minecraft.client.multiplayer.GuiConnecting

Stacktrace:

at net.minecraft.client.Minecraft.runTick(Minecraft.java:1751)

at net.minecraft.client.Minecraft.runGameLoop(Minecraft.java:1038)

at net.minecraft.client.Minecraft.run(Minecraft.java:961)

at net.minecraft.client.main.Main.main(Main.java:164)

at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)

at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)

at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)

at java.lang.reflect.Method.invoke(Unknown Source)

at net.minecraft.launchwrapper.Launch.launch(Launch.java:134)

at net.minecraft.launchwrapper.Launch.main(Launch.java:28)

at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)

at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)

at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)

at java.lang.reflect.Method.invoke(Unknown Source)

at GradleStart.bounce(GradleStart.java:108)

at GradleStart.startClient(GradleStart.java:101)

at GradleStart.main(GradleStart.java:66)

 

It appears to be a problem with the new UUIDs. Is there perhaps a parameter like --username that sets a valid UUID? Or is there any other workaround / fix?

[TehSeph]

--username takes the actual Mojang login username (more than likely your email), not the display name, and needs to be paired with --password.

[jamioflan]

Setting these didn't work. I got the same problem with lack of UUID

[FLUFFY2]

You have to login with two original account if you want to test out the lan stuff.

 

Just to know if you open up a dedicated server and two client you can test stuff out there. If its working there it will work on LAN too. Mostly....