Error: Internal compiler error java.lang.IncompatibleClassChangeError:

Question

I'm using IDE: Eclipse Indigo with jre7, GWT SDK 2.4 for my GWT Project. While compiling project, I got the following error message:

[ERROR]  Internal compiler error
java.lang.IncompatibleClassChangeError: com.google.gwt.user.client.rpc.impl.RemoteServiceProxy and com.google.gwt.user.client.rpc.impl.RemoteServiceProxy$ServiceHelper disagree on InnerClasses attribute
    at java.lang.Class.getDeclaringClass(Native Method)
    at java.lang.Class.getEnclosingClass(Unknown Source)
    at java.lang.Class.getCanonicalName(Unknown Source)
    at com.google.gwt.user.rebind.rpc.ProxyCreator.generateProxyMethod(ProxyCreator.java:497)
    at com.google.gwt.user.rebind.rpc.ProxyCreator.generateProxyMethods(ProxyCreator.java:605)
    at com.google.gwt.user.rebind.rpc.ProxyCreator.create(ProxyCreator.java:332)
    at com.google.gwt.user.rebind.rpc.ServiceInterfaceProxyGenerator.generateIncrementally(ServiceInterfaceProxyGenerator.java:60)
    at com.google.gwt.dev.javac.StandardGeneratorContext.runGeneratorIncrementally(StandardGeneratorContext.java:647)
    at com.google.gwt.dev.cfg.RuleGenerateWith.realize(RuleGenerateWith.java:41)
    at com.google.gwt.dev.shell.StandardRebindOracle$Rebinder.rebind(StandardRebindOracle.java:78)
    at com.google.gwt.dev.shell.StandardRebindOracle.rebind(StandardRebindOracle.java:268)
    at com.google.gwt.dev.shell.StandardRebindOracle.rebind(StandardRebindOracle.java:257)
    at com.google.gwt.dev.DistillerRebindPermutationOracle.getAllPossibleRebindAnswers(DistillerRebindPermutationOracle.java:91)
    at com.google.gwt.dev.jdt.WebModeCompilerFrontEnd.doFindAdditionalTypesUsingRebinds(WebModeCompilerFrontEnd.java:96)
    at com.google.gwt.dev.jdt.AbstractCompiler$Sandbox$CompilerImpl.process(AbstractCompiler.java:254)
    at org.eclipse.jdt.internal.compiler.Compiler.compile(Compiler.java:444)
    at com.google.gwt.dev.jdt.AbstractCompiler$Sandbox$CompilerImpl.compile(AbstractCompiler.java:173)
    at com.google.gwt.dev.jdt.AbstractCompiler$Sandbox$CompilerImpl.compile(AbstractCompiler.java:288)
    at com.google.gwt.dev.jdt.AbstractCompiler$Sandbox$CompilerImpl.access$400(AbstractCompiler.java:139)
    at com.google.gwt.dev.jdt.AbstractCompiler.compile(AbstractCompiler.java:588)
    at com.google.gwt.dev.jdt.BasicWebModeCompiler.getCompilationUnitDeclarations(BasicWebModeCompiler.java:97)
    at com.google.gwt.dev.jdt.WebModeCompilerFrontEnd.getCompilationUnitDeclarations(WebModeCompilerFrontEnd.java:52)
    at com.google.gwt.dev.jjs.JavaToJavaScriptCompiler.precompile(JavaToJavaScriptCompiler.java:569)
    at com.google.gwt.dev.jjs.JavaScriptCompiler.precompile(JavaScriptCompiler.java:33)
    at com.google.gwt.dev.Precompile.precompile(Precompile.java:284)
    at com.google.gwt.dev.Precompile.precompile(Precompile.java:233)
    at com.google.gwt.dev.Precompile.precompile(Precompile.java:145)
    at com.google.gwt.dev.Compiler.run(Compiler.java:232)
    at com.google.gwt.dev.Compiler.run(Compiler.java:198)
    at com.google.gwt.dev.Compiler$1.run(Compiler.java:170)
    at com.google.gwt.dev.CompileTaskRunner.doRun(CompileTaskRunner.java:88)
    at com.google.gwt.dev.CompileTaskRunner.runWithAppropriateLogger(CompileTaskRunner.java:82)
    at com.google.gwt.dev.Compiler.main(Compiler.java:177)

What could be causing this error?

Answer 1

There is a very interesting question that you can take a look at on SO, here it is - the question I was pointing to!

This error is generally due to changes made to any of the non-static, non-private fields/methods to static or vice versa. There is an interesting point that you can learn from each of those answers, which will help you narrow down the actual issue that you are facing right now.

The Client and the Server side code of your RPC call should be your first point to check where this issue should be (the referring jars or the created GWT *.js files)

Hope this helps!