Recently I have had a problem with my Dev environment as IntelliJ cannot find the GradleStart class, therefore it won't run the mod. I'm not sure what has happened as it occurred randomly and I have never had this problem before. When I try to run the minecraft client I get this message.

Exception in thread "main" java.lang.ClassFormatError: Incompatible magic value 3098645073 in class file GradleStart

at java.lang.ClassLoader.defineClass1(Native Method)

at java.lang.ClassLoader.defineClass(ClassLoader.java:800)

at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142)

at java.net.URLClassLoader.defineClass(URLClassLoader.java:449)

at java.net.URLClassLoader.access$100(URLClassLoader.java:71)

at java.net.URLClassLoader$1.run(URLClassLoader.java:361)

at java.net.URLClassLoader$1.run(URLClassLoader.java:355)

at java.security.AccessController.doPrivileged(Native Method)

at java.net.URLClassLoader.findClass(URLClassLoader.java:354)

at java.lang.ClassLoader.loadClass(ClassLoader.java:425)

at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308)

at java.lang.ClassLoader.loadClass(ClassLoader.java:358)

at java.lang.Class.forName0(Native Method)

at java.lang.Class.forName(Class.java:190)

at com.intellij.rt.execution.application.AppMain.main(AppMain.java:116)

 

If you wish to see the project here is the GitHub: https://github.com/PlasmaBlazer/ElectronicEngineering/tree/dev

 

 

Any help would be appreciated. Thanks,

-Plasma

 

Solution:

Seems like your gradle cache got seriously corrupted. Delete the entire .gradle folder in your user home (not in your forge folder!). Then run gradlew setupDecompWorkspace eclipse again (you will have to do this in any workspaces you have, as deleting the gradle cache destroys the workspaces).

Try running

gradlew cleanCache

then

gradlew setupDecompWorkspace --refresh-dependencies

 

and see if that fixes the problem.

Try running

gradlew cleanCache

then

gradlew setupDecompWorkspace --refresh-dependencies

 

and see if that fixes the problem.

 

The "gradlew setupDecompWorkspace --refresh-dependencies" didn't work, it gave this error message:

 

FAILURE: Build failed with an exception.

           

* What went wrong:

Execution failed for task ':extractMcpData'.

> java.util.zip.ZipException: error in opening zip file

           

* Try:     

Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output.

           

BUILD FAILED

i dont know how to delete comments i found out the problem for my self it was because i didnt read the readme

Edited April 1, 20223 yr by A Forge User
found out the error