GWT compilation fails with emma - InvocationTargetException; nested exception is null: Illegal local variable

Question

Have you run into problems with emma when running in a Java7 environment even though your code is compiling as java 1.6?

I have a multimodule build with jdk 1.7 for the majority and jdk 1.6 for GWT modules and their dependencies (or so I thought - I suspect I'm mistaken on this point and this is the core of my problem).

Failed to execute goal org.apache.maven.plugins:maven-surefire-plugin:2.9:test 
(default-test) on project ...: Execution default-test of goal 
org.apache.maven.plugins:maven-surefire-plugin:2.9:test failed: java.lang.reflect.InvocationTargetException; nested exception is 
java.lang.reflect.InvocationTargetException: null: Illegal local variable 
table length 16 in method ....<init>()V -> [Help 1]

Please let me know if there's a known issue or workaround for GWT and emma.

Thanks

Peter

Answer 1

The problem appears to be incompatible java7 byte code in dependent modules. Setting source and target to 1.6 for our base modules which support GWT resolved the problem. GWT presently reports compatibility with 1.5 but 1.6 seems to work without an issue. 1.7 however, is a problem.

    <plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-compiler-plugin</artifactId>
    ...
    <configuration>
      <source>1.6</source>
      <target>1.6</target>
    </configuration>