Hello everyone.

*Full disclosure, I am a noob @ Gradle & brute-forced my way through this

 

I am working on a mod that requires Java 1.8 (Nashorn JS Engine) - and had trouble getting MC Forge to compile and run for me.  It seems that Forge's version of objectweb's bytecode manipulation library has issues with Java 1.8.  Objectweb's latest version fixes the issues & you can use their latest library by adding the following code to your mod's build.gradle:

configurations.all {

    resolutionStrategy.eachDependency { DependencyResolveDetails details ->

        if (details.requested.group == 'org.ow2.asm' && details.requested.name == 'asm-debug-all' && details.requested.version == '4.1') {

            //prefer different version which contains some necessary fixes

            details.useVersion '5.0.1'

        }

    }

}

 

Before adding this, I got build errors like:

 

 

:deobfBinJar

Applying SpecialSource...

INFO: merging AccessMap net/minecraft/item/ItemBlock/field_150939_a from AccessChange(clear=0, set=0, vis=1) with AccessChange(clear=0, set=0, vis=1)

:deobfBinJar FAILED

 

FAILURE: Build failed with an exception.

 

* What went wrong:

Execution failed for task ':deobfBinJar'.

> java.lang.IllegalArgumentException (no error message)

 

* Try:

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

 

 

and

 

 

:deobfuscateJar FAILED

 

FAILURE: Build failed with an exception.

 

* What went wrong:

Execution failed for task ':deobfuscateJar'.

> java.lang.IllegalArgumentException (no error message)

 

* Try:

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

 

BUILD FAILED

 

Total time: 28.114 secs

 

 

 

I also got runtime errors after IntelliJ builds about class load errors (seemingly also related to the objectweb bytecode manipulation libs) but I couldn't reproduce the logs after fixing the issue (I still don't understand Gradle caching )

 

Hope this helps those working with Java 8.

I gave up trying to use java 8. Everything was fine for me except for that :deobf task failing and that you cannot make the mod work on a 1.6 or 1.7 JVM. That leaves out a whole lot of mod users.