In this thread, Nicolas De Loof writes: I solved the issue of compiling the application code for Java 1.3 AND using java5 for tests : Application code is compiled based on java 1.3 using compiler bootclasspath argument. Tests are compiled by adding a compiler execution prior to test-phase (as I didn't find a way to configure testCompile to use a != configuration). Here is my POM : <plugin> <gro