I tried to learn about access transformers. I coded a few classes and I was about to test it, but I was unable to launch Minecraft at all and it doesn't seem the error comes from my injection.

I ended up with ClassNotFoundException with net.minecraftforge.transformers.ForgeAccessTransformer and weirdly I can find the class in the forge Jar.

Here's my run configurations:

VM args: -Dfml.ignoreInvalidMinecraftCertificates=true -Dfml.coreMods.load=com.ringosham.transform.TransformerPlugin

Program args: --version 1.7.10 --tweakClass cpw.mods.fml.common.launcher.FMLTweaker --accessToken modTest --userProperites {} --username Ringowhs --assetIndex 1.7.10 --assetsDir C:\Users\*USERNAME*\.gradle\caches\minecraft\assets

Here's the whole error. I tried refreshing dependencies with gradle and it still doesn't work. This mod originally does not use transformers at all and it runs well in Eclipse. I probably did something stupid that I don't know, but please help me.

[00:55:36] [main/ERROR] [LaunchWrapper]: A critical problem occurred registering the ASM transformer class 
net.minecraftforge.transformers.ForgeAccessTransformer
java.lang.ClassNotFoundException: net.minecraftforge.transformers.ForgeAccessTransformer
at net.minecraft.launchwrapper.LaunchClassLoader.findClass(LaunchClassLoader.java:191) ~[launchwrapper-1.12.jar:?]
at java.lang.ClassLoader.loadClass(Unknown Source) ~[?:1.8.0_73]
at java.lang.ClassLoader.loadClass(Unknown Source) ~[?:1.8.0_73]
at net.minecraft.launchwrapper.LaunchClassLoader.registerTransformer(LaunchClassLoader.java:88) [launchwrapper-1.12.jar:?]
at cpw.mods.fml.common.launcher.FMLDeobfTweaker.injectIntoClassLoader(FMLDeobfTweaker.java:32) [forgeSrc-1.7.10-10.13.4.1614-1.7.10.jar:?]
at net.minecraft.launchwrapper.Launch.launch(Launch.java:115) [launchwrapper-1.12.jar:?]
at net.minecraft.launchwrapper.Launch.main(Launch.java:28) [launchwrapper-1.12.jar:?]
at net.minecraftforge.gradle.GradleStartCommon.launch(Unknown Source) [start/:?]
at GradleStart.main(Unknown Source) [start/:?]
Caused by: java.lang.ClassCircularityError: scala/actors/threadpool/Arrays
at com.ringosham.transform.TransformerClass.transform(TransformerClass.java:28) ~[bin/:?]
at net.minecraft.launchwrapper.LaunchClassLoader.runTransformers(LaunchClassLoader.java:279) ~[launchwrapper-1.12.jar:?]
at net.minecraft.launchwrapper.LaunchClassLoader.findClass(LaunchClassLoader.java:176) ~[launchwrapper-1.12.jar:?]
... 8 more
[00:55:36] [main/INFO] [sTDOUT]: [cpw.mods.fml.common.launcher.FMLDeobfTweaker:injectIntoClassLoader:49]: A CRITICAL PROBLEM OCCURED INITIALIZING MINECRAFT - LIKELY YOU HAVE AN INCORRECT VERSION FOR THIS FML
[00:55:36] [main/ERROR] [LaunchWrapper]: Unable to launch
java.lang.RuntimeException: java.lang.ClassNotFoundException: cpw.mods.fml.common.Loader
at cpw.mods.fml.common.launcher.FMLDeobfTweaker.injectIntoClassLoader(FMLDeobfTweaker.java:50) ~[forgeSrc-1.7.10-10.13.4.1614-1.7.10.jar:?]
at net.minecraft.launchwrapper.Launch.launch(Launch.java:115) [launchwrapper-1.12.jar:?]
at net.minecraft.launchwrapper.Launch.main(Launch.java:28) [launchwrapper-1.12.jar:?]
at net.minecraftforge.gradle.GradleStartCommon.launch(Unknown Source) [start/:?]
at GradleStart.main(Unknown Source) [start/:?]
Caused by: java.lang.ClassNotFoundException: cpw.mods.fml.common.Loader
at net.minecraft.launchwrapper.LaunchClassLoader.findClass(LaunchClassLoader.java:191) ~[launchwrapper-1.12.jar:?]
at java.lang.ClassLoader.loadClass(Unknown Source) ~[?:1.8.0_73]
at java.lang.ClassLoader.loadClass(Unknown Source) ~[?:1.8.0_73]
at java.lang.Class.forName0(Native Method) ~[?:1.8.0_73]
at java.lang.Class.forName(Unknown Source) ~[?:1.8.0_73]
at cpw.mods.fml.common.launcher.FMLDeobfTweaker.injectIntoClassLoader(FMLDeobfTweaker.java:39) ~[forgeSrc-1.7.10-10.13.4.1614-1.7.10.jar:?]
... 4 more
Caused by: java.lang.ClassCircularityError: scala/actors/threadpool/Arrays
at com.ringosham.transform.TransformerClass.transform(TransformerClass.java:28) ~[bin/:?]
at net.minecraft.launchwrapper.LaunchClassLoader.runTransformers(LaunchClassLoader.java:279) ~[launchwrapper-1.12.jar:?]
at net.minecraft.launchwrapper.LaunchClassLoader.findClass(LaunchClassLoader.java:176) ~[launchwrapper-1.12.jar:?]
at java.lang.ClassLoader.loadClass(Unknown Source) ~[?:1.8.0_73]
at java.lang.ClassLoader.loadClass(Unknown Source) ~[?:1.8.0_73]
at java.lang.Class.forName0(Native Method) ~[?:1.8.0_73]
at java.lang.Class.forName(Unknown Source) ~[?:1.8.0_73]
at cpw.mods.fml.common.launcher.FMLDeobfTweaker.injectIntoClassLoader(FMLDeobfTweaker.java:39) ~[forgeSrc-1.7.10-10.13.4.1614-1.7.10.jar:?]
... 4 more
Exception in thread "main" [00:55:36] [main/INFO] [sTDERR]: [java.lang.Throwable$WrappedPrintStream:println:-1]: cpw.mods.fml.relauncher.FMLSecurityManager$ExitTrappedException
[00:55:36] [main/INFO] [sTDERR]: [java.lang.Throwable$WrappedPrintStream:println:-1]: 	at cpw.mods.fml.relauncher.FMLSecurityManager.checkPermission(FMLSecurityManager.java:25)
[00:55:36] [main/INFO] [sTDERR]: [java.lang.Throwable$WrappedPrintStream:println:-1]: 	at java.lang.SecurityManager.checkExit(Unknown Source)
[00:55:36] [main/INFO] [sTDERR]: [java.lang.Throwable$WrappedPrintStream:println:-1]: 	at java.lang.Runtime.exit(Unknown Source)
[00:55:36] [main/INFO] [sTDERR]: [java.lang.Throwable$WrappedPrintStream:println:-1]: 	at java.lang.System.exit(Unknown Source)
[00:55:36] [main/INFO] [sTDERR]: [java.lang.Throwable$WrappedPrintStream:println:-1]: 	at net.minecraft.launchwrapper.Launch.launch(Launch.java:138)
[00:55:36] [main/INFO] [sTDERR]: [java.lang.Throwable$WrappedPrintStream:println:-1]: 	at net.minecraft.launchwrapper.Launch.main(Launch.java:28)
[00:55:36] [main/INFO] [sTDERR]: [java.lang.Throwable$WrappedPrintStream:println:-1]: 	at net.minecraftforge.gradle.GradleStartCommon.launch(Unknown Source)
[00:55:36] [main/INFO] [sTDERR]: [java.lang.Throwable$WrappedPrintStream:println:-1]: 	at GradleStart.main(Unknown Source)

 

 

Why are you trying to edit classes?

I was trying to intercept any outgoing chat messages by changing the EntityClientPlayerMP.sendChatMessage

I know that there is a way to do that with some networking(or SimpleNetworkWrapper/netty/whatever) stuff as you told me before, but the methods I found in the tutorials doesn't seem that there are answers. I found tutorials about sending and receiving packets from and to servers, but I cannot seem to find anything from catching outbound packets.