Is there any reason why EclEmma(JaCoCo based) in Eclipse falsely reports the code coverage while using the GwtMockitoTestRunner?
Looking at it's source code, it does install it's own class loader and does byte code manipulation using the Javassist library. Could this affect the code coverage tool anyhow?
It looks like the issue is that EclEmma/JaCoCo doesn't work well with final methods and with native methods(GWT JSNI code).
Fixing these methods everything returned to normal, the coverage is reported correctly.