Please close if this is too far off the topic.

So I have decompiled 1.13. I have set it up in IntelliJ.
I have then fixed the dependencies so that they are all found.
The issue I am having is when I try run, it attempts to start but then crashing with the following error:

"A:\Program Files\Java\jdk1.8.0_101\bin\java" -Djava.library.path=versions\1.13\1.13-natives -Didea.launcher.port=7538 "-Didea.launcher.bin.path=A:\Program Files (x86)\JetBrains\IntelliJ IDEA Community Edition 2016.2.2\bin" -Dfile.encoding=UTF-8 -classpath "{{A BUNCH OF STUFF NOT RELEVANT TO THIS ERROR}}A:\Users\Joel\Documents\Code\Minecraft\MCP Fixer\mcp940\jars\libraries\org\lwjgl\lwjgl-glfw\3.1.6\lwjgl-glfw-3.1.6.jar;A:\Users\Joel\Documents\Code\Minecraft\MCP Fixer\mcp940\jars\libraries\org\lwjgl\lwjgl-stb\3.1.6\lwjgl-stb-3.1.6.jar;A:\Users\Joel\Documents\Code\Minecraft\MCP Fixer\mcp940\jars\libraries\org\lwjgl\lwjgl-openal\3.1.6\lwjgl-openal-3.1.6.jar;A:\Users\Joel\Documents\Code\Minecraft\MCP Fixer\mcp940\jars\libraries\org\lwjgl\lwjgl\3.1.6\lwjgl-3.1.6.jar;A:\Users\Joel\Documents\Code\Minecraft\MCP Fixer\mcp940\jars\libraries\org\lwjgl\lwjgl-opengl\3.1.6\lwjgl-opengl-3.1.6.jar;A:\Users\Joel\Documents\Code\Minecraft\MCP Fixer\mcp940\jars\libraries\org\lwjgl\lwjgl\3.1.6\lwjgl-3.1.6-natives-windows.jar;A:\Program Files (x86)\JetBrains\IntelliJ IDEA Community Edition 2016.2.2\lib\idea_rt.jar" com.intellij.rt.execution.application.AppMain mcp.client.Start
[09:20:12] [Client thread/INFO]: Setting user: Player125
[09:20:14] [Client thread/INFO]: LWJGL Version: 3.1.6 build 14
---- Minecraft Crash Report ----
// Why did you do that?

Time: 3/07/19 9:20 AM
Description: Initializing game

java.lang.IllegalStateException: GLFW error 65542: WGL: The driver does not appear to support OpenGL
	at net.minecraft.client.MainWindow.throwExceptionForGlError(MainWindow.java:226)
	at org.lwjgl.glfw.GLFWErrorCallbackI.callback(GLFWErrorCallbackI.java:36)
	at org.lwjgl.system.JNI.invokePPPP(Native Method)
	at org.lwjgl.glfw.GLFW.nglfwCreateWindow(GLFW.java:1649)
	at org.lwjgl.glfw.GLFW.glfwCreateWindow(GLFW.java:1827)
	at net.minecraft.client.MainWindow.<init>(MainWindow.java:91)
	at net.minecraft.client.renderer.VirtualScreen.createMainWindow(VirtualScreen.java:103)
	at net.minecraft.client.Minecraft.init(Minecraft.java:502)
	at net.minecraft.client.Minecraft.run(Minecraft.java:424)
	at net.minecraft.client.main.Main.main(Main.java:129)
	at mcp.client.Start.main(Start.java:12)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:498)
	at com.intellij.rt.execution.application.AppMain.main(AppMain.java:147)


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

-- Head --
Thread: Client thread
Stacktrace:
	at net.minecraft.client.MainWindow.throwExceptionForGlError(MainWindow.java:226)
	at org.lwjgl.glfw.GLFWErrorCallbackI.callback(GLFWErrorCallbackI.java:36)
	at org.lwjgl.system.JNI.invokePPPP(Native Method)
	at org.lwjgl.glfw.GLFW.nglfwCreateWindow(GLFW.java:1649)
	at org.lwjgl.glfw.GLFW.glfwCreateWindow(GLFW.java:1827)
	at net.minecraft.client.MainWindow.<init>(MainWindow.java:91)
	at net.minecraft.client.renderer.VirtualScreen.createMainWindow(VirtualScreen.java:103)
	at net.minecraft.client.Minecraft.init(Minecraft.java:502)

-- Initialization --
Details:
Stacktrace:
	at net.minecraft.client.Minecraft.run(Minecraft.java:424)
	at net.minecraft.client.main.Main.main(Main.java:129)
	at mcp.client.Start.main(Start.java:12)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:498)
	at com.intellij.rt.execution.application.AppMain.main(AppMain.java:147)

-- System Details --
Details:
	Minecraft Version: 1.13
	Operating System: Windows 8.1 (amd64) version 6.3
	Java Version: 1.8.0_101, Oracle Corporation
	Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Oracle Corporation
	Memory: 141613024 bytes (135 MB) / 279445504 bytes (266 MB) up to 3808428032 bytes (3632 MB)
	JVM Flags: 0 total; 
	Launched Version: mcp
	LWJGL: 3.1.6 build 14
	OpenGL: NO CONTEXT
	GL Caps: 
	Using VBOs: Yes
	Is Modded: Very likely; Jar signature invalidated
	Type: Client (map_client.txt)
	Resource Packs: 
	Current Language: ~~ERROR~~ NullPointerException: null
	Profiler Position: N/A (disabled)
	CPU: <unknown>
#@!@# Game crashed! Crash report saved to: #@!@# A:\Users\Joel\Documents\Code\Minecraft\MCP Fixer\mcp940\jars\.\crash-reports\crash-2019-07-03_09.20.14-client.txt

Process finished with exit code -1

So its something to do with dependencies I assume, Do you know what I need to add or change to get this to run?

Thanks!

Edit:
When I change around some of the dependences I can get this error:

[09:45:41] [Client thread/INFO]: Setting user: Player848
[09:45:42] [Client thread/INFO]: LWJGL Version: 3.1.6 build 14
[09:45:42] [Client thread/INFO]: [STDERR]: [LWJGL] Failed to load a library. Possible solutions:
	a) Add the directory that contains the shared library to -Djava.library.path or -Dorg.lwjgl.librarypath.
	b) Add the JAR that contains the shared library to the classpath.
[09:45:42] [Client thread/INFO]: [STDERR]: [LWJGL] Enable debug mode with -Dorg.lwjgl.util.Debug=true for better diagnostics.
[09:45:42] [Client thread/INFO]: [STDERR]: [LWJGL] Enable the SharedLibraryLoader debug mode with -Dorg.lwjgl.util.DebugLoader=true for better diagnostics.

So, one thing that happened is that whenever I try and run something over 1.15.2+, it just stuck on 'Decompiling'. This never happened in previous versions, any ideas?

I'm doing 1.16 (with the right mappings, getting those mappings I strongly recommend using MCPReborn just to locate the .jar with the field, methods, params, etc: but, I use this tool because I like it more.)

Hi
First off, great work here!
So I am trying to decompile 1.13 with the instructions you provided.
I must have done something wrong but I cant work out where I went wrong. Below is the error I am getting. Would you be able to shed some light on where I messed up?

== MCP 9.40 (data: 9.41, client: 1.13, server: 1.13) ==
"scalac" is not found on the PATH.  Scala files will not be recompiled
# found ff patches, srgs, name csvs, doc csvs, param csvs, astyle, astyle config
, rg, ss
!! need either jad or fernflower available with patches !!
Press any key to continue . . .

I am unsure what it means by need either jad or fernflower available with patches as I copied over fernflower.jar into that correct location.

Thanks in advance!

java version "1.8.0_101"
Here is what my mcp940>runtime>bin folder looks like

So I have tried a few things.
First time I was able to decompile successfully but it failed to recompile.

At this stage I forgot to do the step For 1.14 and up, search for IgnorePkg, and delete com from the list.
The reason it failed to compile was listed here:
recompile Error.txt

I then realized I missed that step and tried again.

I first tried removing the IgnorePkg line from mcp.cfg but then comands.py complained as it couldn't find that key/line.

So then I went and commented out every line that contained IgnorePkg in commands.py (There were 11 instances found in total).

I then got this error:

== MCP 9.40 (data: 9.42, client: 1.14.3, server: 1.14.3) ==
"scalac" is not found on the PATH.  Scala files will not be recompiled
# found ff, ff patches, srgs, name csvs, doc csvs, param csvs, astyle, astyle co
nfig, rg, ss
!! Modified jar detected. Unpredictable results !!
== Decompiling client using fernflower ==
> Creating SRGs
> Applying SpecialSource
> Applying MCInjector
> Creating renamed srg
> Filtering classes
FATAL ERROR
Traceback (most recent call last):
  File "runtime\decompile.py", line 144, in decompile
    joined=only_joined)
  File "A:\Users\Joel\Documents\Code\Minecraft\MCP Fixer\1.14.3\mcp940\runtime\m
cp.py", line 45, in decompile_side
    commands.filterffjar(side)
  File "A:\Users\Joel\Documents\Code\Minecraft\MCP Fixer\1.14.3\mcp940\runtime\c
ommands.py", line 1370, in filterffjar
    for p in self.ignorepkg:
AttributeError: 'Commands' object has no attribute 'ignorepkg'
Press any key to continue . . .

Are you able to explain that step again as I must have done something wrong?

Hi, great work with this project.
One issue I am having is that its failing when trying to find or create minecraft_ff_in.jar
Below is the full log

== MCP 9.40 (data: 9.41, client: 1.13, server: 1.13) ==
"scalac" is not found on the PATH.  Scala files will not be recompiled
# found ff, ff patches, srgs, name csvs, doc csvs, param csvs, astyle, astyle co
nfig, rg, ss
!! Modified jar detected. Unpredictable results !!
== Decompiling client using fernflower ==
> Creating SRGs
> Applying SpecialSource
> Applying MCInjector
> Creating renamed srg
> Filtering classes
> Decompiling
FATAL ERROR
Traceback (most recent call last):
  File "runtime\decompile.py", line 145, in decompile joined=only_joined)
  File "A:\Users\Joel\Documents\Code\Minecraft\MCP Fixer\mcp940\runtime\mcp.py", line 47, in decompile_side commands.applyff(side)
  File "A:\Users\Joel\Documents\Code\Minecraft\MCP Fixer\mcp940\runtime\commands.py", line 1402, in applyff shutil.move(jarout, ffoutput[side])
  File "shutil.pyc", line 299, in move
  File "shutil.pyc", line 128, in copy2
  File "shutil.pyc", line 82, in copyfile IOError: [Errno 2] No such file or directory: 'temp\\src\\minecraft\\minecraft_ff_in.jar'
Press any key to continue . . .

After it breaks, this is my folder structure in mcp940>temp:

The mcp940>temp>src>minecraft folder is there but empty

Do you have any ideas why this is happening or what I need to do to fix it?

For some reason using normal MCPConfig doesn't work, as hunk apply fails and recompile errors. For now I have created a fork at https://github.com/MicherGit/MCPFixer-Config with code from commit 0cdc6055297f0b30cf3e27e59317f229a30863a6 that can be used instead. This seems to be mappings related as in commit e829c04 the forge guys changed how MCPConfig applies mappings and is still broken.

Do I just run the "Fixer.jar" in the folder with all the files? I'm not exactly sure what to do.

== MCP 9.18 (data: 9.18, client: 1.8.8, server: 1.8.8) ==
"scalac" is not found on the PATH. Scala files will not be recompiled

found ff, ff patches, srgs, name csvs, doc csvs, param csvs, astyle, astyle config, rg, ss

Looking in C:\Users\preti\AppData\Roaming.minecraft\versions for mc installs... OK
Copying assets... OK
Parsing JSON file... OK
Looking for minecraft main jar... Not found
Copying minecraft main jar... OK

Checking libraries...
Copying library jinput... OK
Copying library lwjgl-platform... OK
Copying library icu4j-core-mojang... OK
Copying library twitch-external-platform... OK
Copying library httpcore... OK
Copying library log4j-api... OK
Copying library commons-lang3... OK
Copying library jna... OK
Copying library libraryjavasound... OK
Copying library jopt-simple... OK
Copying library guava... OK
Copying library oshi-core... OK
Copying library httpclient... OK
Copying library commons-compress... OK
Copying library platform... OK
Copying library codecjorbis... OK
Copying library soundsystem... OK
Copying library librarylwjglopenal... OK
Copying library lwjgl_util... OK
Copying library commons-codec... OK
Copying library jutils... OK
Copying library commons-logging... OK
Copying library lwjgl... OK
Copying library commons-io... OK
Copying library realms... OK
Copying library authlib... OK
Copying library gson... OK
Copying library netty... OK
Copying library twitch... OK
Copying library codecwav... OK
Copying library twitch-platform... OK
Copying library jinput-platform... OK
Copying library log4j-core... OK
Copying library netty-all... OK
Checking Natives...
Extracting native avutil-ttv-51.dll... OK
Extracting native lwjgl.dll... OK
Extracting native OpenAL32.dll... OK
Extracting native jinput-dx8_64.dll... OK
Extracting native libmfxsw64.dll... OK
Extracting native jinput-wintab.dll... OK
Extracting native twitchsdk.dll... OK
Extracting native jinput-dx8.dll... OK
Extracting native libmp3lame-ttv.dll... OK
Extracting native jinput-raw.dll... OK
Extracting native OpenAL64.dll... OK
Extracting native jinput-raw_64.dll... OK
Extracting native swresample-ttv-0.dll... OK
Extracting native lwjgl64.dll... OK
== Decompiling client using fernflower ==
Creating SRGs
Applying SpecialSource
Applying MCInjector
Creating renamed srg
Filtering classes
Decompiling
'"C:\Program Files\Java\jdk1.8.0_281\bin\java" -jar runtime\bin\fernflower.jar -din=1 -rbr=1 -dgs=1 -asc=1 -rsy=1 -iec=1 -jvn=1 -log=WARN "-e=jars\libraries\net/java/jinput\jinput\2.0.5\jinput-2.0.5.jar" "-e=jars\libraries\org/lwjgl/lwjgl\lwjgl-platform\2.9.4-nightly-20150209\lwjgl-platform-2.9.4-nightly-20150209-natives-windows.jar" "-e=jars\libraries\com/ibm/icu\icu4j-core-mojang\51.2\icu4j-core-mojang-51.2.jar" "-e=jars\libraries\tv/twitch\twitch-external-platform\4.5\twitch-external-platform-4.5-natives-windows-64.jar" "-e=jars\libraries\org/apache/httpcomponents\httpcore\4.3.2\httpcore-4.3.2.jar" "-e=jars\libraries\org/apache/logging/log4j\log4j-api\2.0-beta9\log4j-api-2.0-beta9.jar" "-e=jars\libraries\org/apache/commons\commons-lang3\3.3.2\commons-lang3-3.3.2.jar" "-e=jars\libraries\net/java/dev/jna\jna\3.4.0\jna-3.4.0.jar" "-e=jars\libraries\com/paulscode\libraryjavasound\20101123\libraryjavasound-20101123.jar" "-e=jars\libraries\net/sf/jopt-simple\jopt-simple\4.6\jopt-simple-4.6.jar" "-e=jars\libraries\com/google/guava\guava\17.0\guava-17.0.jar" "-e=jars\libraries\oshi-project\oshi-core\1.1\oshi-core-1.1.jar" "-e=jars\libraries\org/apache/httpcomponents\httpclient\4.3.3\httpclient-4.3.3.jar" "-e=jars\libraries\org/apache/commons\commons-compress\1.8.1\commons-compress-1.8.1.jar" "-e=jars\libraries\net/java/dev/jna\platform\3.4.0\platform-3.4.0.jar" "-e=jars\libraries\com/paulscode\codecjorbis\20101023\codecjorbis-20101023.jar" "-e=jars\libraries\com/paulscode\soundsystem\20120107\soundsystem-20120107.jar" "-e=jars\libraries\com/paulscode\librarylwjglopenal\20100824\librarylwjglopenal-20100824.jar" "-e=jars\libraries\org/lwjgl/lwjgl\lwjgl_util\2.9.4-nightly-20150209\lwjgl_util-2.9.4-nightly-20150209.jar" "-e=jars\libraries\commons-codec\commons-codec\1.9\commons-codec-1.9.jar" "-e=jars\libraries\net/java/jutils\jutils\1.0.0\jutils-1.0.0.jar" "-e=jars\libraries\commons-logging\commons-logging\1.1.3\commons-logging-1.1.3.jar" "-e=jars\libraries\org/lwjgl/lwjgl\lwjgl\2.9.4-nightly-20150209\lwjgl-2.9.4-nightly-20150209.jar" "-e=jars\libraries\commons-io\commons-io\2.4\commons-io-2.4.jar" "-e=jars\libraries\com/mojang\realms\1.7.39\realms-1.7.39.jar" "-e=jars\libraries\com/mojang\authlib\1.5.21\authlib-1.5.21.jar" "-e=jars\libraries\com/google/code/gson\gson\2.2.4\gson-2.2.4.jar" "-e=jars\libraries\com/mojang\netty\1.6\netty-1.6.jar" "-e=jars\libraries\tv/twitch\twitch\6.5\twitch-6.5.jar" "-e=jars\libraries\com/paulscode\codecwav\20101023\codecwav-20101023.jar" "-e=jars\libraries\tv/twitch\twitch-platform\6.5\twitch-platform-6.5-natives-windows-64.jar" "-e=jars\libraries\net/java/jinput\jinput-platform\2.0.5\jinput-platform-2.0.5-natives-windows.jar" "-e=jars\libraries\org/apache/logging/log4j\log4j-core\2.0-beta9\log4j-core-2.0-beta9.jar" "-e=jars\libraries\io/netty\netty-all\4.0.23.Final\netty-all-4.0.23.Final.jar" temp/minecraft_ff_in.jar temp\src\minecraft' failed : 1
Decompile failed
Pressione qualquer tecla para continuar. . .

Not going to do a pull request, since this doesn't actually change any code.

I realized I had forgotten to attribute the link below when writing the getArchClassifier() method.
https://github.com/HyCraftHD/Minecraft-Downloader/blob/main/src/main/java/net/hycrafthd/minecraft_downloader/util/OSUtil.java

There isn't a whole lot of inspiration, but I felt it right to include it anyway.

Sorry for not including it originally, and sorry for waiting so long to bring it up.

Thanks.

What is the licence for this piece of software?
I was hoping to be able to re-make it in C#.

I use the way and the tool you provide and I found that something error.
Before decompiled the MCP, I found that there wasn't a Start.java in conf/patches and inject folder.
So, I copy them from origin MCP folder then I can decompile it.
When I trying to Run Client, it start success with icon and background.
But on the Main Menu all font are just rectangles, the world's texture are lost.
Some textures not lost are like items(blocks) added in 1.13 and entities.
I don't know how to solve it.

There is my log:

[13:45:45] [Client thread/INFO]: Setting user: Player655
[13:45:47] [Client thread/WARN]: Skipping bad option: lastServer:
[13:45:47] [Client thread/INFO]: LWJGL Version: 3.1.6 build 14
[13:45:48] [Client thread/INFO]: Reloading ResourceManager: Default
[13:45:48] [Client thread/WARN]: Missing sound for event: minecraft:ambient.cave
[13:45:48] [Client thread/WARN]: Missing sound for event: minecraft:ambient.underwater.enter
... ...
[13:45:48] [Sound Library Loader/INFO]: Starting up SoundSystem...
[13:45:49] [Thread-2/INFO]: Initializing No Sound
[13:45:49] [Thread-2/INFO]: (Silent Mode)
[13:45:49] [Thread-2/INFO]: OpenAL initialized.
[13:45:49] [Sound Library Loader/INFO]: Sound engine started
[13:45:50] [Client thread/ERROR]: Using missing texture, unable to load minecraft:textures/block/oak_door_top.png : java.io.FileNotFoundException: minecraft:textures/block/oak_door_top.png
[13:45:50] [Client thread/ERROR]: Using missing texture, unable to load minecraft:textures/block/tnt_bottom.png : java.io.FileNotFoundException: minecraft:textures/block/tnt_bottom.png
... ...
[13:45:58] [Server thread/INFO]: Preparing spawn area: 4%
... ...
java.lang.IllegalArgumentException: Data fixer not registered for: minecraft:DUMMY in block_entity
at com.mojang.datafixers.schemas.Schema.getChoiceType(Schema.java:107) ~[datafixerupper-1.0.19.jar:?]
at net.minecraft.util.datafix.NamespacedSchema.getChoiceType(NamespacedSchema.java:23) ~[bin/:?]
at net.minecraft.util.datafix.fixes.NamedEntityFix.makeRule(NamedEntityFix.java:27) ~[bin/:?]
at com.mojang.datafixers.DataFix.getRule(DataFix.java:97) ~[datafixerupper-1.0.19.jar:?]
at com.mojang.datafixers.DataFixerUpper.getRule(DataFixerUpper.java:135) ~[datafixerupper-1.0.19.jar:?]
at com.mojang.datafixers.DataFixerUpper.update(DataFixerUpper.java:83) ~[datafixerupper-1.0.19.jar:?]
at net.minecraft.nbt.NBTUtil.update(NBTUtil.java:345) ~[bin/:?]
at net.minecraft.nbt.NBTUtil.update(NBTUtil.java:340) ~[bin/:?]
at net.minecraft.world.gen.feature.template.TemplateManager.loadTemplate(TemplateManager.java:168) ~[bin/:?]
at net.minecraft.world.gen.feature.template.TemplateManager.loadTemplateResource(TemplateManager.java:82) ~[bin/:?]
at net.minecraft.world.gen.feature.template.TemplateManager.lambda$0(TemplateManager.java:66) ~[bin/:?]
at java.util.HashMap.computeIfAbsent(Unknown Source) [?:1.8.0_201]
at net.minecraft.world.gen.feature.template.TemplateManager.getTemplate(TemplateManager.java:63) [bin/:?]
at net.minecraft.world.gen.feature.template.TemplateManager.getTemplateDefaulted(TemplateManager.java:49) [bin/:?]
at net.minecraft.world.gen.feature.structure.ShipwreckPieces$Piece.func_204754_a(ShipwreckPieces.java:77) [bin/:?]
at net.minecraft.world.gen.feature.structure.ShipwreckPieces$Piece.readAdditional(ShipwreckPieces.java:72) [bin/:?]
at net.minecraft.world.gen.feature.structure.StructurePiece.read(StructurePiece.java:95) [bin/:?]
at net.minecraft.world.gen.feature.structure.StructureIO.getStructureComponent(StructureIO.java:102) [bin/:?]
at net.minecraft.world.gen.feature.structure.StructureStart.read(StructureStart.java:139) [bin/:?]
at net.minecraft.world.gen.feature.structure.StructureIO.func_202602_a(StructureIO.java:70) [bin/:?]
at net.minecraft.world.chunk.storage.AnvilChunkLoader.readStructureStartsFromNBT(AnvilChunkLoader.java:915) [bin/:?]
at net.minecraft.world.chunk.storage.AnvilChunkLoader.readChunkFromNBT(AnvilChunkLoader.java:662) [bin/:?]
at net.minecraft.world.chunk.storage.AnvilChunkLoader.checkedReadChunkFromNBT(AnvilChunkLoader.java:228) [bin/:?]
at net.minecraft.world.chunk.storage.AnvilChunkLoader.loadChunk(AnvilChunkLoader.java:154) [bin/:?]
at net.minecraft.world.gen.ChunkProviderServer.getChunk(ChunkProviderServer.java:124) [bin/:?]
at net.minecraft.world.gen.ChunkProviderServer.loadChunks(ChunkProviderServer.java:174) [bin/:?]
at net.minecraft.server.MinecraftServer.initialWorldChunkLoad(MinecraftServer.java:485) [bin/:?]
at net.minecraft.server.integrated.IntegratedServer.loadAllWorlds(IntegratedServer.java:90) [bin/:?]
at net.minecraft.server.integrated.IntegratedServer.init(IntegratedServer.java:106) [bin/:?]
at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:699) [bin/:?]
at java.lang.Thread.run(Unknown Source) [?:1.8.0_201]
... ...

I found a weird issue where the launch scripts by default don't work due to Start.class not being recompiled in the right location. If anyone else has this issue I will probably leave this here as a workaround until an official fix is released if a fix is possible.

Issue

Start.java is in package mcp.client which is unrecognized by the launch scripts.

This is the error I get-

== MCP 9.40 (data: 9.52, client: 1.13.2, server: 1.13.2) ==
"scalac" is not found on the PATH.  Scala files will not be recompiled
[11:52:03] Error: Could not find or load main class Start
[11:52:03] OpenJDK 64-Bit Server VM warning: Using incremental CMS is deprecated and will likely be removed in a future release
'"C:\Program Files\AdoptOpenJDK\jdk-8.0.275.1-hotspot\bin\java" -Xincgc -Xms1024M -Xmx1024M -cp "..\bin\minecraft;..\src\minecraft;..\jars\versions\1.13.2\1.13.2.jar;..\lib;..\lib\*;..\jars\libraries\com\google\code\findbugs\jsr305\3.0.1\jsr305-3.0.1.jar;..\jars\libraries\net\java\jinput\jinput\2.0.5\jinput-2.0.5.jar;..\jars\libraries\org\lwjgl\lwjgl-stb\3.1.6\lwjgl-stb-3.1.6.jar;..\jars\libraries\com\ibm\icu\icu4j-core-mojang\51.2\icu4j-core-mojang-51.2.jar;..\jars\libraries\org\apache\httpcomponents\httpcore\4.3.2\httpcore-4.3.2.jar;..\jars\libraries\org\apache\logging\log4j\log4j-api\2.8.1\log4j-api-2.8.1.jar;..\jars\libraries\org\apache\commons\commons-lang3\3.5\commons-lang3-3.5.jar;..\jars\libraries\org\lwjgl\lwjgl\3.1.6\lwjgl-3.1.6-natives-windows.jar;..\jars\libraries\net\java\dev\jna\jna\4.4.0\jna-4.4.0.jar;..\jars\libraries\com\paulscode\libraryjavasound\20101123\libraryjavasound-20101123.jar;..\jars\libraries\net\sf\jopt-simple\jopt-simple\5.0.3\jopt-simple-5.0.3.jar;..\jars\libraries\com\mojang\text2speech\1.10.3\text2speech-1.10.3.jar;..\jars\libraries\com\mojang\datafixerupper\1.0.19\datafixerupper-1.0.19.jar;..\jars\libraries\com\google\guava\guava\21.0\guava-21.0.jar;..\jars\libraries\oshi-project\oshi-core\1.1\oshi-core-1.1.jar;..\jars\libraries\org\lwjgl\lwjgl-jemalloc\3.1.6\lwjgl-jemalloc-3.1.6.jar;..\jars\libraries\org\apache\httpcomponents\httpclient\4.3.3\httpclient-4.3.3.jar;..\jars\libraries\org\apache\commons\commons-compress\1.8.1\commons-compress-1.8.1.jar;..\jars\libraries\com\mojang\text2speech\1.10.3\text2speech-1.10.3-natives-windows.jar;..\jars\libraries\it\unimi\dsi\fastutil\8.2.1\fastutil-8.2.1.jar;..\jars\libraries\net\java\dev\jna\platform\3.4.0\platform-3.4.0.jar;..\jars\libraries\com\paulscode\codecjorbis\20101023\codecjorbis-20101023.jar;..\jars\libraries\com\paulscode\soundsystem\20120107\soundsystem-20120107.jar;..\jars\libraries\commons-codec\commons-codec\1.10\commons-codec-1.10.jar;..\jars\libraries\net\java\jutils\jutils\1.0.0\jutils-1.0.0.jar;..\jars\libraries\com\mojang\patchy\1.1\patchy-1.1.jar;..\jars\libraries\org\lwjgl\lwjgl-opengl\3.1.6\lwjgl-opengl-3.1.6.jar;..\jars\libraries\commons-logging\commons-logging\1.1.3\commons-logging-1.1.3.jar;..\jars\libraries\org\lwjgl\lwjgl-jemalloc\3.1.6\lwjgl-jemalloc-3.1.6-natives-windows.jar;..\jars\libraries\org\lwjgl\lwjgl-glfw\3.1.6\lwjgl-glfw-3.1.6.jar;..\jars\libraries\com\mojang\brigadier\1.0.14\brigadier-1.0.14.jar;..\jars\libraries\org\lwjgl\lwjgl-opengl\3.1.6\lwjgl-opengl-3.1.6-natives-windows.jar;..\jars\libraries\org\lwjgl\lwjgl\3.1.6\lwjgl-3.1.6.jar;..\jars\libraries\commons-io\commons-io\2.5\commons-io-2.5.jar;..\jars\libraries\com\mojang\realms\1.13.9\realms-1.13.9.jar;..\jars\libraries\com\mojang\authlib\1.5.25\authlib-1.5.25.jar;..\jars\libraries\com\google\code\gson\gson\2.8.0\gson-2.8.0.jar;..\jars\libraries\org\lwjgl\lwjgl-glfw\3.1.6\lwjgl-glfw-3.1.6-natives-windows.jar;..\jars\libraries\com\paulscode\codecwav\20101023\codecwav-20101023.jar;..\jars\libraries\org\lwjgl\lwjgl-stb\3.1.6\lwjgl-stb-3.1.6-natives-windows.jar;..\jars\libraries\org\lwjgl\lwjgl-openal\3.1.6\lwjgl-openal-3.1.6.jar;..\jars\libraries\org\apache\logging\log4j\log4j-core\2.8.1\log4j-core-2.8.1.jar;..\jars\libraries\org\lwjgl\lwjgl-openal\3.1.6\lwjgl-openal-3.1.6-natives-windows.jar;..\jars\libraries\io\netty\netty-all\4.1.25.Final\netty-all-4.1.25.Final.jar" -Djava.library.path=..\jars\versions\1.13.2\1.13.2-natives Start' failed : 1
FATAL ERROR
Traceback (most recent call last):
  File "runtime\startclient.py", line 43, in startclient
  File "C:\Users\user\Downloads\mcp952\runtime\commands.py", line 1678, in startclient
    self.runmc(forkcmd)
  File "C:\Users\user\Downloads\mcp952\runtime\commands.py", line 1718, in runmc
    raise CalledProcessError(process.returncode, forkcmd, output)
CalledProcessError: Command '"C:\Program Files\AdoptOpenJDK\jdk-8.0.275.1-hotspot\bin\java" -Xincgc -Xms1024M -Xmx1024M -cp "..\bin\minecraft;..\src\minecraft;..\jars\versions\1.13.2\1.13.2.jar;..\lib;..\lib\*;..\jars\libraries\com\google\code\findbugs\jsr305\3.0.1\jsr305-3.0.1.jar;..\jars\libraries\net\java\jinput\jinput\2.0.5\jinput-2.0.5.jar;..\jars\libraries\org\lwjgl\lwjgl-stb\3.1.6\lwjgl-stb-3.1.6.jar;..\jars\libraries\com\ibm\icu\icu4j-core-mojang\51.2\icu4j-core-mojang-51.2.jar;..\jars\libraries\org\apache\httpcomponents\httpcore\4.3.2\httpcore-4.3.2.jar;..\jars\libraries\org\apache\logging\log4j\log4j-api\2.8.1\log4j-api-2.8.1.jar;..\jars\libraries\org\apache\commons\commons-lang3\3.5\commons-lang3-3.5.jar;..\jars\libraries\org\lwjgl\lwjgl\3.1.6\lwjgl-3.1.6-natives-windows.jar;..\jars\libraries\net\java\dev\jna\jna\4.4.0\jna-4.4.0.jar;..\jars\libraries\com\paulscode\libraryjavasound\20101123\libraryjavasound-20101123.jar;..\jars\libraries\net\sf\jopt-simple\jopt-simple\5.0.3\jopt-simple-5.0.3.jar;..\jars\libraries\com\mojang\text2speech\1.10.3\text2speech-1.10.3.jar;..\jars\libraries\com\mojang\datafixerupper\1.0.19\datafixerupper-1.0.19.jar;..\jars\libraries\com\google\guava\guava\21.0\guava-21.0.jar;..\jars\libraries\oshi-project\oshi-core\1.1\oshi-core-1.1.jar;..\jars\libraries\org\lwjgl\lwjgl-jemalloc\3.1.6\lwjgl-jemalloc-3.1.6.jar;..\jars\libraries\org\apache\httpcomponents\httpclient\4.3.3\httpclient-4.3.3.jar;..\jars\libraries\org\apache\commons\commons-compress\1.8.1\commons-compress-1.8.1.jar;..\jars\libraries\com\mojang\text2speech\1.10.3\text2speech-1.10.3-natives-windows.jar;..\jars\libraries\it\unimi\dsi\fastutil\8.2.1\fastutil-8.2.1.jar;..\jars\libraries\net\java\dev\jna\platform\3.4.0\platform-3.4.0.jar;..\jars\libraries\com\paulscode\codecjorbis\20101023\codecjorbis-20101023.jar;..\jars\libraries\com\paulscode\soundsystem\20120107\soundsystem-20120107.jar;..\jars\libraries\commons-codec\commons-codec\1.10\commons-codec-1.10.jar;..\jars\libraries\net\java\jutils\jutils\1.0.0\jutils-1.0.0.jar;..\jars\libraries\com\mojang\patchy\1.1\patchy-1.1.jar;..\jars\libraries\org\lwjgl\lwjgl-opengl\3.1.6\lwjgl-opengl-3.1.6.jar;..\jars\libraries\commons-logging\commons-logging\1.1.3\commons-logging-1.1.3.jar;..\jars\libraries\org\lwjgl\lwjgl-jemalloc\3.1.6\lwjgl-jemalloc-3.1.6-natives-windows.jar;..\jars\libraries\org\lwjgl\lwjgl-glfw\3.1.6\lwjgl-glfw-3.1.6.jar;..\jars\libraries\com\mojang\brigadier\1.0.14\brigadier-1.0.14.jar;..\jars\libraries\org\lwjgl\lwjgl-opengl\3.1.6\lwjgl-opengl-3.1.6-natives-windows.jar;..\jars\libraries\org\lwjgl\lwjgl\3.1.6\lwjgl-3.1.6.jar;..\jars\libraries\commons-io\commons-io\2.5\commons-io-2.5.jar;..\jars\libraries\com\mojang\realms\1.13.9\realms-1.13.9.jar;..\jars\libraries\com\mojang\authlib\1.5.25\authlib-1.5.25.jar;..\jars\libraries\com\google\code\gson\gson\2.8.0\gson-2.8.0.jar;..\jars\libraries\org\lwjgl\lwjgl-glfw\3.1.6\lwjgl-glfw-3.1.6-natives-windows.jar;..\jars\libraries\com\paulscode\codecwav\20101023\codecwav-20101023.jar;..\jars\libraries\org\lwjgl\lwjgl-stb\3.1.6\lwjgl-stb-3.1.6-natives-windows.jar;..\jars\libraries\org\lwjgl\lwjgl-openal\3.1.6\lwjgl-openal-3.1.6.jar;..\jars\libraries\org\apache\logging\log4j\log4j-core\2.8.1\log4j-core-2.8.1.jar;..\jars\libraries\org\lwjgl\lwjgl-openal\3.1.6\lwjgl-openal-3.1.6-natives-windows.jar;..\jars\libraries\io\netty\netty-all\4.1.25.Final\netty-all-4.1.25.Final.jar" -Djava.library.path=..\jars\versions\1.13.2\1.13.2-natives Start' returned non-zero exit status 1
Press any key to continue . . .

Fix

Remove a single line of code, package mcp.client from Start.java before recompiling and launching.

Versions affected

From my testing, 1.15.2 and 1.13.2, but most versions except 1.12.2 are probably affected in some way.

i m having this err can anyone help
== MCP 9.18 (data: 9.18, client: 1.8.8, server: 1.8.8) ==

Searching for javac.exe in C:\Program Files\Java\jre1.8.0_301
Searching for javac.exe in C:\Program Files
Searching for javac.exe in C:\Program Files (x86)
"scalac" is not found on the PATH. Scala files will not be recompiled
!! Can not find client bins !!
Press any key to continue . . .

Everything is working perfectly, however, most of the classes and code are affected because javax.annotation cannot be found (or javax in general), any reason why?

If it helps:
AdoptOpenJDK 8 is what I'm using

Hey, ive been trying to decompile minecraft 1.8.8 cause im trying to make a client, However i get errors and i don't know how to solve them, if someone could help me it would be great, thanks!

== MCP 9.18 (data: 9.18, client: 1.8.8, server: 1.8.8) ==
Searching for javac.exe in C:\Program Files
"scalac" is not found on the PATH. Scala files will not be recompiled

found ff, ff patches, srgs, name csvs, doc csvs, param csvs, astyle, astyle config, rg, ss

== Decompiling client using fernflower ==

Creating SRGs
Applying SpecialSource
Applying MCInjector
Creating renamed srg
Filtering classes
Decompiling
Unpacking jar
Copying sources
Applying fernflower fixes
Applying patches
'runtime\bin\applydiff.exe -p1 -u -i ....\temp\temp.patch -d src\minecraft' failed : 1

== ERRORS FOUND ==

1 out of 1 hunk FAILED -- saving rejects to file 'net\minecraft\util\Cartesian.jav#'

Cleaning comments

• Done in 296.62 seconds
  == Reformating client ==

Cleaning sources
Replacing OpenGL constants
Reformating sources

• Done in 37.89 seconds
  == Updating client ==

Adding javadoc
Renaming sources

• Done in 41.92 seconds
  == Decompiling server using fernflower ==

Creating SRGs
Applying SpecialSource
Applying MCInjector
Creating renamed srg
Filtering classes
Decompiling
Unpacking jar
Copying sources
Applying fernflower fixes
Applying patches
'runtime\bin\applydiff.exe -p1 -u -i ....\temp\temp.patch -d src\minecraft_server' failed : 1

== ERRORS FOUND ==

1 out of 1 hunk FAILED -- saving rejects to file 'net\minecraft\util\Cartesian.jav#'

Cleaning comments

• Done in 111.68 seconds
  == Reformating server ==

Cleaning sources
Reformating sources

• Done in 25.08 seconds
  == Updating server ==

Adding javadoc
Renaming sources

• Done in 26.25 seconds
  == Recompiling client ==

Cleaning bin
Recompiling
'"C:\Program Files\Java\jdk-11.0.3\bin\javac" -Xlint:-options -deprecation -g -source 1.6 -target 1.6 -classpath "jars\versions\1.8.8\1.8.8.jar;lib;lib*;jars\libraries\net\java\jinput\jinput\2.0.5\jinput-2.0.5.jar;jars\libraries\org\lwjgl\lwjgl\lwjgl-platform\2.9.4-nightly-20150209\lwjgl-platform-2.9.4-nightly-20150209-natives-windows.jar;jars\libraries\com\ibm\icu\icu4j-core-mojang\51.2\icu4j-core-mojang-51.2.jar;jars\libraries\tv\twitch\twitch-external-platform\4.5\twitch-external-platform-4.5-natives-windows-64.jar;jars\libraries\org\apache\httpcomponents\httpcore\4.3.2\httpcore-4.3.2.jar;jars\libraries\org\apache\logging\log4j\log4j-api\2.0-beta9\log4j-api-2.0-beta9.jar;jars\libraries\org\apache\commons\commons-lang3\3.3.2\commons-lang3-3.3.2.jar;jars\libraries\net\java\dev\jna\jna\3.4.0\jna-3.4.0.jar;jars\libraries\com\paulscode\libraryjavasound\20101123\libraryjavasound-20101123.jar;jars\libraries\net\sf\jopt-simple\jopt-simple\4.6\jopt-simple-4.6.jar;jars\libraries\com\google\guava\guava\17.0\guava-17.0.jar;jars\libraries\oshi-project\oshi-core\1.1\oshi-core-1.1.jar;jars\libraries\org\apache\httpcomponents\httpclient\4.3.3\httpclient-4.3.3.jar;jars\libraries\org\apache\commons\commons-compress\1.8.1\commons-compress-1.8.1.jar;jars\libraries\net\java\dev\jna\platform\3.4.0\platform-3.4.0.jar;jars\libraries\com\paulscode\codecjorbis\20101023\codecjorbis-20101023.jar;jars\libraries\com\paulscode\soundsystem\20120107\soundsystem-20120107.jar;jars\libraries\com\paulscode\librarylwjglopenal\20100824\librarylwjglopenal-20100824.jar;jars\libraries\org\lwjgl\lwjgl\lwjgl_util\2.9.4-nightly-20150209\lwjgl_util-2.9.4-nightly-20150209.jar;jars\libraries\commons-codec\commons-codec\1.9\commons-codec-1.9.jar;jars\libraries\net\java\jutils\jutils\1.0.0\jutils-1.0.0.jar;jars\libraries\commons-logging\commons-logging\1.1.3\commons-logging-1.1.3.jar;jars\libraries\org\lwjgl\lwjgl\lwjgl\2.9.4-nightly-20150209\lwjgl-2.9.4-nightly-20150209.jar;jars\libraries\commons-io\commons-io\2.4\commons-io-2.4.jar;jars\libraries\com\mojang\realms\1.7.39\realms-1.7.39.jar;jars\libraries\com\mojang\authlib\1.5.21\authlib-1.5.21.jar;jars\libraries\com\google\code\gson\gson\2.2.4\gson-2.2.4.jar;jars\libraries\com\mojang\netty\1.6\netty-1.6.jar;jars\libraries\tv\twitch\twitch\6.5\twitch-6.5.jar;jars\libraries\com\paulscode\codecwav\20101023\codecwav-20101023.jar;jars\libraries\tv\twitch\twitch-platform\6.5\twitch-platform-6.5-natives-windows-64.jar;jars\libraries\net\java\jinput\jinput-platform\2.0.5\jinput-platform-2.0.5-natives-windows.jar;jars\libraries\org\apache\logging\log4j\log4j-core\2.0-beta9\log4j-core-2.0-beta9.jar;jars\libraries\io\netty\netty-all\4.0.23.Final\netty-all-4.0.23.Final.jar" -sourcepath src\minecraft -d bin\minecraft @temp\java_src_client.txt' failed : 1

== ERRORS FOUND in JAVA CODE ==

src\minecraft\net\minecraft\util\ObjectIntIdentityMap.java:21: error: incompatible types: Object cannot be converted to T
this.objectList.add((Object)null);
^

where T is a type-variable:
T extends Object declared in class ObjectIntIdentityMap
src\minecraft\net\minecraft\tileentity\TileEntity.java:108: warning: [deprecation] newInstance() in Class has been deprecated
tileentity = (TileEntity)oclass.newInstance();
^

where T is a type-variable:
T extends Object declared in class Class
src\minecraft\net\minecraft\inventory\Container.java:39: error: incompatible types: Object cannot be converted to ItemStack
this.inventoryItemStacks.add((Object)null);
^

src\minecraft\net\minecraft\network\NetHandlerPlayServer.java:445: error: incompatible types: Set cannot be converted to Set
this.setPlayerLocation(x, y, z, yaw, pitch, Collections.emptySet());
^

src\minecraft\net\minecraft\network\NetworkSystem.java:78: error: incompatible types: List cannot be converted to List
private final List endpoints = Collections.synchronizedList(Lists.newArrayList());
^

src\minecraft\net\minecraft\network\NetworkSystem.java:79: error: incompatible types: List cannot be converted to List
private final List networkManagers = Collections.synchronizedList(Lists.newArrayList());
^

src\minecraft\net\minecraft\network\EnumConnectionState.java:291: warning: [deprecation] newInstance() in Class has been deprecated
return oclass == null ? null : (Packet)oclass.newInstance();
^

where T is a type-variable:
T extends Object declared in class Class
src\minecraft\net\minecraft\network\EnumConnectionState.java:332: warning: [deprecation] newInstance() in Class has been deprecated
oclass.newInstance();
^

where T is a type-variable:
T extends Object declared in class Class
src\minecraft\net\minecraft\entity\item\EntityMinecart.java:97: warning: [deprecation] Integer(int) in Integer has been deprecated
this.dataWatcher.addObject(17, new Integer(0));
^

src\minecraft\net\minecraft\entity\item\EntityMinecart.java:98: warning: [deprecation] Integer(int) in Integer has been deprecated
this.dataWatcher.addObject(18, new Integer(1));
^

src\minecraft\net\minecraft\entity\item\EntityMinecart.java:99: warning: [deprecation] Float(float) in Float has been deprecated
this.dataWatcher.addObject(19, new Float(0.0F));
^

src\minecraft\net\minecraft\entity\item\EntityMinecart.java:100: warning: [deprecation] Integer(int) in Integer has been deprecated
this.dataWatcher.addObject(20, new Integer(0));
^

src\minecraft\net\minecraft\entity\item\EntityMinecart.java:101: warning: [deprecation] Integer(int) in Integer has been deprecated
this.dataWatcher.addObject(21, new Integer(6));
^

src\minecraft\net\minecraft\block\BlockRedstoneTorch.java:27: error: incompatible types: ArrayList cannot be converted to List
toggles.put(worldIn, Lists.newArrayList());
^

src\minecraft\net\minecraft\block\state\pattern\FactoryBlockPattern.java:26: error: incompatible types: Predicate cannot be converted to Predicate
this.symbolMap.put(' ', Predicates.alwaysTrue());
^

src\minecraft\net\minecraft\block\state\pattern\FactoryBlockPattern.java:56: error: incompatible types: Object cannot be converted to Predicate
this.symbolMap.put(Character.valueOf(c0), (Object)null);
^

src\minecraft\net\minecraft\client\Minecraft.java:811: error: incompatible types: List cannot be converted to List<ResourcePackRepository.Entry>
this.mcResourcePackRepository.setRepositories(Collections.emptyList());
^

src\minecraft\net\minecraft\client\renderer\texture\TextureAtlasSprite.java:382: error: incompatible types: Object cannot be converted to int[][]
this.framesTextureData.add((Object)null);
^

src\minecraft\net\minecraft\world\gen\FlatGeneratorInfo.java:300: error: incompatible types: HashMap<Object,Object> cannot be converted to Map<String,String>
flatgeneratorinfo.getWorldFeatures().put("village", Maps.newHashMap());
^

src\minecraft\net\minecraft\world\gen\FlatGeneratorInfo.java:325: error: incompatible types: HashMap<Object,Object> cannot be converted to Map<String,String>
flatgeneratorinfo.getWorldFeatures().put("village", Maps.newHashMap());
^

src\minecraft\net\minecraft\client\gui\GuiFlatPresets.java:176: error: incompatible types: HashMap<Object,Object> cannot be converted to Map<String,String>
flatgeneratorinfo.getWorldFeatures().put(s, Maps.newHashMap());
^

src\minecraft\net\minecraft\client\network\OldServerPinger.java:50: error: incompatible types: List cannot be converted to List
private final List pingDestinations = Collections.synchronizedList(Lists.newArrayList());
^

src\minecraft\net\minecraft\client\gui\GuiScreenRealmsProxy.java:18: error: incompatible types: List cannot be converted to List
super.buttonList = Collections.synchronizedList(Lists.newArrayList());
^

src\minecraft\net\minecraft\client\renderer\block\model\ModelBlock.java:55: error: incompatible types: List cannot be converted to List
this(parentLocationIn, Collections.emptyList(), texturesIn, ambientOcclusionIn, gui3dIn, cameraTransformsIn);
^

src\minecraft\net\minecraft\entity\passive\EntityBat.java:29: warning: [deprecation] Byte(byte) in Byte has been deprecated
this.dataWatcher.addObject(16, new Byte((byte)0));
^

src\minecraft\net\minecraft\entity\monster\EntityBlaze.java:55: warning: [deprecation] Byte(byte) in Byte has been deprecated
this.dataWatcher.addObject(16, new Byte((byte)0));
^

src\minecraft\net\minecraft\entity\item\EntityBoat.java:56: warning: [deprecation] Integer(int) in Integer has been deprecated
this.dataWatcher.addObject(17, new Integer(0));
^

src\minecraft\net\minecraft\entity\item\EntityBoat.java:57: warning: [deprecation] Integer(int) in Integer has been deprecated
this.dataWatcher.addObject(18, new Integer(1));
^

src\minecraft\net\minecraft\entity\item\EntityBoat.java:58: warning: [deprecation] Float(float) in Float has been deprecated
this.dataWatcher.addObject(19, new Float(0.0F));
^

src\minecraft\net\minecraft\entity\monster\EntitySpider.java:67: warning: [deprecation] Byte(byte) in Byte has been deprecated
this.dataWatcher.addObject(16, new Byte((byte)0));
^

src\minecraft\net\minecraft\entity\monster\EntityEnderman.java:84: warning: [deprecation] Short(short) in Short has been deprecated
this.dataWatcher.addObject(16, new Short((short)0));
^

src\minecraft\net\minecraft\entity\monster\EntityEnderman.java:85: warning: [deprecation] Byte(byte) in Byte has been deprecated
this.dataWatcher.addObject(17, new Byte((byte)0));
^

src\minecraft\net\minecraft\entity\monster\EntityEnderman.java:86: warning: [deprecation] Byte(byte) in Byte has been deprecated
this.dataWatcher.addObject(18, new Byte((byte)0));
^

src\minecraft\net\minecraft\entity\passive\EntityWolf.java:131: warning: [deprecation] Float(float) in Float has been deprecated
this.dataWatcher.addObject(18, new Float(this.getHealth()));
^

src\minecraft\net\minecraft\entity\passive\EntityWolf.java:132: warning: [deprecation] Byte(byte) in Byte has been deprecated
this.dataWatcher.addObject(19, new Byte((byte)0));
^

src\minecraft\net\minecraft\entity\passive\EntityWolf.java:133: warning: [deprecation] Byte(byte) in Byte has been deprecated
this.dataWatcher.addObject(20, new Byte((byte)EnumDyeColor.RED.getMetadata()));
^

src\minecraft\net\minecraft\entity\passive\EntitySheep.java:111: warning: [deprecation] Byte(byte) in Byte has been deprecated
this.dataWatcher.addObject(16, new Byte((byte)0));
^

src\minecraft\net\minecraft\entity\monster\EntitySkeleton.java:76: warning: [deprecation] Byte(byte) in Byte has been deprecated
this.dataWatcher.addObject(13, new Byte((byte)0));
^

src\minecraft\net\minecraft\entity\boss\EntityWither.java:79: warning: [deprecation] Integer(int) in Integer has been deprecated
this.dataWatcher.addObject(17, new Integer(0));
^

src\minecraft\net\minecraft\entity\boss\EntityWither.java:80: warning: [deprecation] Integer(int) in Integer has been deprecated
this.dataWatcher.addObject(18, new Integer(0));
^

src\minecraft\net\minecraft\entity\boss\EntityWither.java:81: warning: [deprecation] Integer(int) in Integer has been deprecated
this.dataWatcher.addObject(19, new Integer(0));
^

src\minecraft\net\minecraft\entity\boss\EntityWither.java:82: warning: [deprecation] Integer(int) in Integer has been deprecated
this.dataWatcher.addObject(20, new Integer(0));
^

src\minecraft\net\minecraft\client\resources\FallbackResourceManager.java:122: warning: [deprecation] finalize() in Object has been deprecated
protected void finalize() throws Throwable
^

src\minecraft\net\minecraft\client\resources\FallbackResourceManager.java:129: warning: [deprecation] finalize() in Object has been deprecated
super.finalize();
^

src\minecraft\net\minecraft\client\resources\FileResourcePack.java:108: warning: [deprecation] finalize() in Object has been deprecated
protected void finalize() throws Throwable
^

src\minecraft\net\minecraft\client\resources\FileResourcePack.java:111: warning: [deprecation] finalize() in Object has been deprecated
super.finalize();
^

src\minecraft\net\minecraft\client\resources\FolderResourcePack.java:36: error: reference to listFiles is ambiguous
for (File file2 : file1.listFiles(DirectoryFileFilter.DIRECTORY))
^

both method listFiles(FilenameFilter) in File and method listFiles(FileFilter) in File match
src\minecraft\net\minecraft\client\resources\model\SimpleBakedModel.java:116: error: incompatible types: ArrayList cannot be converted to List
this.builderFaceQuads.add(Lists.newArrayList());
^

src\minecraft\net\minecraft\command\CommandSpreadPlayers.java:138: error: incompatible types: Object cannot be converted to Team
set.add((Object)null);
^

src\minecraft\net\minecraft\entity\ai\attributes\ModifiableAttributeInstance.java:33: error: incompatible types: HashSet cannot be converted to Set
this.mapByOperation.put(Integer.valueOf(i), Sets.newHashSet());
^

src\minecraft\net\minecraft\entity\item\EntityMinecartFurnace.java:41: warning: [deprecation] Byte(byte) in Byte has been deprecated
this.dataWatcher.addObject(16, new Byte((byte)0));
^

src\minecraft\net\minecraft\realms\RealmsServerStatusPinger.java:28: error: incompatible types: List cannot be converted to List
private final List connections = Collections.synchronizedList(Lists.newArrayList());
^

src\minecraft\net\minecraft\util\Cartesian.java:56: error: incompatible types: List cannot be converted to List
return Arrays.asList((Object[])p_apply_1_);
^

where T is a type-variable:
T extends Object declared in class GetList
src\minecraft\net\minecraft\world\gen\structure\MapGenStructureIO.java:50: warning: [deprecation] newInstance() in Class has been deprecated
structurestart = (StructureStart)oclass.newInstance();
^

where T is a type-variable:
T extends Object declared in class Class
src\minecraft\net\minecraft\world\gen\structure\MapGenStructureIO.java:81: warning: [deprecation] newInstance() in Class has been deprecated
structurecomponent = (StructureComponent)oclass.newInstance();
^

where T is a type-variable:
T extends Object declared in class Class
src\minecraft\net\minecraft\world\gen\structure\StructureMineshaftPieces.java:611: error: cannot find symbol
for (lvt_5_1_ = 0; k < this.boundingBox.getXSize(); k = k + 4)
^

symbol: variable lvt_5_1_
location: class Room
src\minecraft\net\minecraft\world\storage\ThreadedFileIOBase.java:11: error: incompatible types: List cannot be converted to List
private List threadedIOQueue = Collections.synchronizedList(Lists.newArrayList());
^

24 errors
33 warnings

Initial client recompile failed, correct source then run updatemd5
== Recompiling server ==

Cleaning bin
Recompiling
'"C:\Program Files\Java\jdk-11.0.3\bin\javac" -Xlint:-options -deprecation -g -source 1.6 -target 1.6 -classpath "lib;lib*;jars\minecraft_server.1.8.8.jar" -sourcepath src\minecraft_server -d bin\minecraft_server @temp\java_src_server.txt' failed : 1

== ERRORS FOUND in JAVA CODE ==

src\minecraft_server\net\minecraft\util\ObjectIntIdentityMap.java:21: error: incompatible types: Object cannot be converted to T
this.objectList.add((Object)null);
^

where T is a type-variable:
T extends Object declared in class ObjectIntIdentityMap
src\minecraft_server\net\minecraft\tileentity\TileEntity.java:108: warning: [deprecation] newInstance() in Class has been deprecated
tileentity = (TileEntity)oclass.newInstance();
^

where T is a type-variable:
T extends Object declared in class Class
src\minecraft_server\net\minecraft\inventory\Container.java:38: error: incompatible types: Object cannot be converted to ItemStack
this.inventoryItemStacks.add((Object)null);
^

src\minecraft_server\net\minecraft\network\NetHandlerPlayServer.java:445: error: incompatible types: Set cannot be converted to Set
this.setPlayerLocation(x, y, z, yaw, pitch, Collections.emptySet());
^

src\minecraft_server\net\minecraft\network\NetworkSystem.java:74: error: incompatible types: List cannot be converted to List
private final List endpoints = Collections.synchronizedList(Lists.newArrayList());
^

src\minecraft_server\net\minecraft\network\NetworkSystem.java:75: error: incompatible types: List cannot be converted to List
private final List networkManagers = Collections.synchronizedList(Lists.newArrayList());
^

src\minecraft_server\net\minecraft\network\EnumConnectionState.java:291: warning: [deprecation] newInstance() in Class has been deprecated
return oclass == null ? null : (Packet)oclass.newInstance();
^

where T is a type-variable:
T extends Object declared in class Class
src\minecraft_server\net\minecraft\network\EnumConnectionState.java:332: warning: [deprecation] newInstance() in Class has been deprecated
oclass.newInstance();
^

where T is a type-variable:
T extends Object declared in class Class
src\minecraft_server\net\minecraft\entity\item\EntityMinecart.java:94: warning: [deprecation] Integer(int) in Integer has been deprecated
this.dataWatcher.addObject(17, new Integer(0));
^

src\minecraft_server\net\minecraft\entity\item\EntityMinecart.java:95: warning: [deprecation] Integer(int) in Integer has been deprecated
this.dataWatcher.addObject(18, new Integer(1));
^

src\minecraft_server\net\minecraft\entity\item\EntityMinecart.java:96: warning: [deprecation] Float(float) in Float has been deprecated
this.dataWatcher.addObject(19, new Float(0.0F));
^

src\minecraft_server\net\minecraft\entity\item\EntityMinecart.java:97: warning: [deprecation] Integer(int) in Integer has been deprecated
this.dataWatcher.addObject(20, new Integer(0));
^

src\minecraft_server\net\minecraft\entity\item\EntityMinecart.java:98: warning: [deprecation] Integer(int) in Integer has been deprecated
this.dataWatcher.addObject(21, new Integer(6));
^

src\minecraft_server\net\minecraft\block\BlockRedstoneTorch.java:27: error: incompatible types: ArrayList cannot be converted to List
toggles.put(worldIn, Lists.newArrayList());
^

src\minecraft_server\net\minecraft\block\state\pattern\FactoryBlockPattern.java:26: error: incompatible types: Predicate cannot be converted to Predicate
this.symbolMap.put(' ', Predicates.alwaysTrue());
^

src\minecraft_server\net\minecraft\block\state\pattern\FactoryBlockPattern.java:56: error: incompatible types: Object cannot be converted to Predicate
this.symbolMap.put(Character.valueOf(c0), (Object)null);
^

src\minecraft_server\net\minecraft\command\CommandSpreadPlayers.java:138: error: incompatible types: Object cannot be converted to Team
set.add((Object)null);
^

src\minecraft_server\net\minecraft\entity\passive\EntityWolf.java:131: warning: [deprecation] Float(float) in Float has been deprecated
this.dataWatcher.addObject(18, new Float(this.getHealth()));
^

src\minecraft_server\net\minecraft\entity\passive\EntityWolf.java:132: warning: [deprecation] Byte(byte) in Byte has been deprecated
this.dataWatcher.addObject(19, new Byte((byte)0));
^

src\minecraft_server\net\minecraft\entity\passive\EntityWolf.java:133: warning: [deprecation] Byte(byte) in Byte has been deprecated
this.dataWatcher.addObject(20, new Byte((byte)EnumDyeColor.RED.getMetadata()));
^

src\minecraft_server\net\minecraft\entity\ai\attributes\ModifiableAttributeInstance.java:32: error: incompatible types: HashSet cannot be converted to Set
this.mapByOperation.put(Integer.valueOf(i), Sets.newHashSet());
^

src\minecraft_server\net\minecraft\entity\boss\EntityWither.java:79: warning: [deprecation] Integer(int) in Integer has been deprecated
this.dataWatcher.addObject(17, new Integer(0));
^

src\minecraft_server\net\minecraft\entity\boss\EntityWither.java:80: warning: [deprecation] Integer(int) in Integer has been deprecated
this.dataWatcher.addObject(18, new Integer(0));
^

src\minecraft_server\net\minecraft\entity\boss\EntityWither.java:81: warning: [deprecation] Integer(int) in Integer has been deprecated
this.dataWatcher.addObject(19, new Integer(0));
^

src\minecraft_server\net\minecraft\entity\boss\EntityWither.java:82: warning: [deprecation] Integer(int) in Integer has been deprecated
this.dataWatcher.addObject(20, new Integer(0));
^

src\minecraft_server\net\minecraft\entity\item\EntityBoat.java:53: warning: [deprecation] Integer(int) in Integer has been deprecated
this.dataWatcher.addObject(17, new Integer(0));
^

src\minecraft_server\net\minecraft\entity\item\EntityBoat.java:54: warning: [deprecation] Integer(int) in Integer has been deprecated
this.dataWatcher.addObject(18, new Integer(1));
^

src\minecraft_server\net\minecraft\entity\item\EntityBoat.java:55: warning: [deprecation] Float(float) in Float has been deprecated
this.dataWatcher.addObject(19, new Float(0.0F));
^

src\minecraft_server\net\minecraft\entity\item\EntityMinecartFurnace.java:41: warning: [deprecation] Byte(byte) in Byte has been deprecated
this.dataWatcher.addObject(16, new Byte((byte)0));
^

src\minecraft_server\net\minecraft\entity\monster\EntityBlaze.java:55: warning: [deprecation] Byte(byte) in Byte has been deprecated
this.dataWatcher.addObject(16, new Byte((byte)0));
^

src\minecraft_server\net\minecraft\entity\monster\EntitySpider.java:67: warning: [deprecation] Byte(byte) in Byte has been deprecated
this.dataWatcher.addObject(16, new Byte((byte)0));
^

src\minecraft_server\net\minecraft\entity\monster\EntityEnderman.java:84: warning: [deprecation] Short(short) in Short has been deprecated
this.dataWatcher.addObject(16, new Short((short)0));
^

src\minecraft_server\net\minecraft\entity\monster\EntityEnderman.java:85: warning: [deprecation] Byte(byte) in Byte has been deprecated
this.dataWatcher.addObject(17, new Byte((byte)0));
^

src\minecraft_server\net\minecraft\entity\monster\EntityEnderman.java:86: warning: [deprecation] Byte(byte) in Byte has been deprecated
this.dataWatcher.addObject(18, new Byte((byte)0));
^

src\minecraft_server\net\minecraft\entity\monster\EntitySkeleton.java:76: warning: [deprecation] Byte(byte) in Byte has been deprecated
this.dataWatcher.addObject(13, new Byte((byte)0));
^

src\minecraft_server\net\minecraft\entity\passive\EntityBat.java:29: warning: [deprecation] Byte(byte) in Byte has been deprecated
this.dataWatcher.addObject(16, new Byte((byte)0));
^

src\minecraft_server\net\minecraft\entity\passive\EntitySheep.java:110: warning: [deprecation] Byte(byte) in Byte has been deprecated
this.dataWatcher.addObject(16, new Byte((byte)0));
^

src\minecraft_server\net\minecraft\server\dedicated\DedicatedServer.java:41: error: incompatible types: List cannot be converted to List
private final List pendingCommandList = Collections.synchronizedList(Lists.newArrayList());
^

src\minecraft_server\net\minecraft\util\Cartesian.java:56: error: incompatible types: List cannot be converted to List
return Arrays.asList((Object[])p_apply_1_);
^

where T is a type-variable:
T extends Object declared in class GetList
src\minecraft_server\net\minecraft\world\gen\FlatGeneratorInfo.java:300: error: incompatible types: HashMap<Object,Object> cannot be converted to Map<String,String>
flatgeneratorinfo.getWorldFeatures().put("village", Maps.newHashMap());
^

src\minecraft_server\net\minecraft\world\gen\FlatGeneratorInfo.java:325: error: incompatible types: HashMap<Object,Object> cannot be converted to Map<String,String>
flatgeneratorinfo.getWorldFeatures().put("village", Maps.newHashMap());
^

src\minecraft_server\net\minecraft\world\gen\structure\MapGenStructureIO.java:50: warning: [deprecation] newInstance() in Class has been deprecated
structurestart = (StructureStart)oclass.newInstance();
^

where T is a type-variable:
T extends Object declared in class Class
src\minecraft_server\net\minecraft\world\gen\structure\MapGenStructureIO.java:81: warning: [deprecation] newInstance() in Class has been deprecated
structurecomponent = (StructureComponent)oclass.newInstance();
^

where T is a type-variable:
T extends Object declared in class Class
src\minecraft_server\net\minecraft\world\gen\structure\StructureMineshaftPieces.java:611: error: cannot find symbol
for (lvt_5_1_ = 0; k < this.boundingBox.getXSize(); k = k + 4)
^

symbol: variable lvt_5_1_
location: class Room
src\minecraft_server\net\minecraft\world\storage\ThreadedFileIOBase.java:11: error: incompatible types: List cannot be converted to List
private List threadedIOQueue = Collections.synchronizedList(Lists.newArrayList());
^

16 errors
29 warnings

Initial server recompile failed, correct source then run updatemd5

1.16.5 gets stuck here

The last version that I know works is either 1.16.1 or 1.15.2, but I think 1.15.2. Maybe fernflower is too new?

For some reason, even when using MCP mappings, it doesn't work on 1.16 and above, it gets stuck in an endless decompiling loop, and in 1.17 due to forge ditching og mapping system half the files needed in the tutorial don't exist anymore

I followed the tutorial at https://github.com/ThisTestUser/MCPFixer/wiki/Tutorial but got an error saying that it needs mcinjector configs. How do I fix these? where do i get these?

When decompiling 1.19, I followed every step but I still have the same outcome everytime:

Checking libraries...
Copying library netty-resolver... OK
Copying library jna-platform... OK
Copying library httpcore... OK
Copying library log4j-api... OK
Copying library netty-buffer... OK
Copying library jna... OK
Copying library jopt-simple... OK
Copying library text2speech... OK
Copying library datafixerupper... OK
Copying library guava... OK
Copying library oshi-core... OK
Copying library netty-handler... OK
Copying library lwjgl-stb... OK
Copying library commons-logging... OK
Copying library commons-compress... OK
Copying library fastutil... OK
Copying library failureaccess... OK
Copying library lwjgl-tinyfd... OK
Copying library javabridge... OK
Copying library netty-transport-classes-epoll... OK
Copying library slf4j-api... OK
Copying library commons-codec... OK
Copying library httpclient... OK
Copying library patchy... OK
Copying library lwjgl-opengl... OK
Copying library log4j-slf4j18-impl... OK
Copying library netty-transport-native-epoll... Error copying library netty-transport-native-epoll

Can I write 1.14.4 server mods using MCP and MCPFixer?