I keep getting this error message while setting up my work space, I have tried several different versions of forge. This particular error message came from "forge-1.9-12.16.1.1887-mdk".

 

FAILURE: Build failed with an exception.

* What went wrong:
Execution failed for task ':recompileMc'.
> Unable to find a javac compiler;
com.sun.tools.javac.Main is not on the classpath.
Perhaps JAVA_HOME does not point to the JDK.
It is currently set to "C:\Program Files\Java\jre1.8.0_91"

* 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: 39.345 secs

I don't quite know how to fix that but the line below that would seem to contradict it.

I don't know how I can fix this. My "path" environment variable contains "C:\Program Files\Java\jdk1.8.0_51\bin" but not "C:\Program Files\Java\jre1.8.0_91".

That doesn't really help... Is JAVA_HOME supposed to be an environment variable, some sort of java setting, other?

For some reason that environment variable did not already exist... Strange considering I have modded earlier versions of Minecraft without this problem.

I added the variable and it seems to have fixed my problem, thank you!