How can I resolve this IllegalAccessError in org.mozilla.javascript.optimizer.BodyCodegen running on Heroku?

Question

I have googled far and wide and not found any references to this issue, so any help would be much appreciated.

I can regularly generate an illegal access error when using the Java Less compiler ( https://github.com/marceloverdijk/lesscss-java ), but not on my development machine - only on Heroku (and dokku it seems - same issue there). The compiler calls compile on some javascript code, which goes through the optimiser, and fails with the following stack trace:

java.lang.IllegalAccessError: tried to access method org.mozilla.classfile.ClassFileWriter.getLabelPC(I)I from class org.mozilla.javascript.optimizer.BodyCodegen$ExceptionManager
    at org.mozilla.javascript.optimizer.BodyCodegen$ExceptionManager.endCatch(Codegen.java:4051)
    at org.mozilla.javascript.optimizer.BodyCodegen$ExceptionManager.removeHandler(Codegen.java:3952)
    at org.mozilla.javascript.optimizer.BodyCodegen.visitTryCatchFinally(Codegen.java:3705)
    at org.mozilla.javascript.optimizer.BodyCodegen.generateStatement(Codegen.java:1897)
    at org.mozilla.javascript.optimizer.BodyCodegen.generateStatement(Codegen.java:1873)
    at org.mozilla.javascript.optimizer.BodyCodegen.generateStatement(Codegen.java:1858)
    at org.mozilla.javascript.optimizer.BodyCodegen.generateBodyCode(Codegen.java:1289)
    at org.mozilla.javascript.optimizer.Codegen.generateCode(Codegen.java:306)
    at org.mozilla.javascript.optimizer.Codegen.compileToClassFile(Codegen.java:166)
    at org.mozilla.javascript.optimizer.Codegen.compile(Codegen.java:75)
    at org.mozilla.javascript.Context.compileImpl(Context.java:2377)
    at org.mozilla.javascript.Context.compileReader(Context.java:1296)
    at org.lesscss.LessCompiler.init(LessCompiler.java:295)
    at org.lesscss.LessCompiler.compile(LessCompiler.java:357)
    at org.lesscss.LessCompiler.compile(LessCompiler.java:450)

This is particularly odd since the method it fails to call is public ( https://github.com/mozilla/rhino/blob/master/src/org/mozilla/classfile/ClassFileWriter.java#L1260-L1268 ).

As mentioned, I think this has something to do with the Heroku environment, since I cannot replicate this on my development machine.

Any ideas would be gratefully received.

Answer 1

I resolved this by excluding the offending dependency from my build in project.clj , since it wasn't actually needed itself. I'm still not sure why this problem only manifested itself in some environments, but it is now resolved at least.