I cannot launch Minecraft 1.12.2

[LilyPad]

I can run 1.12.2 vanilla and forge without any issues; however, I wanted to use a hacked client and this error was shown in my game logs.

Failed to start Minecraft:
java.lang.reflect.InvocationTargetException
	at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:110)
	at java.base/java.lang.reflect.Method.invoke(Method.java:577)
	at org.multimc.onesix.OneSixLauncher.launchWithMainClass(OneSixLauncher.java:210)
	at org.multimc.onesix.OneSixLauncher.launch(OneSixLauncher.java:245)
	at org.multimc.EntryPoint.listen(EntryPoint.java:143)
	at org.multimc.EntryPoint.main(EntryPoint.java:34)
Caused by: java.lang.ClassCastException: class jdk.internal.loader.ClassLoaders$AppClassLoader cannot be cast to class java.net.URLClassLoader (jdk.internal.loader.ClassLoaders$AppClassLoader and java.net.URLClassLoader are in module java.base of loader 'bootstrap')
	at net.minecraft.launchwrapper.Launch.<init>(Launch.java:34)
	at net.minecraft.launchwrapper.Launch.main(Launch.java:28)
	at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:104)
	... 5 more

I don't really know what happened, I am using MultiMC as my launcher and trying to run the lambda hacked client. 

[sciwhiz12]

The version you are using is no longer supported on this forum.

Please update to a modern version of Minecraft to receive support.

Currently supported versions are 1.19.2 (Latest) and 1.18.2 (LTS).