This is an answer that does not explain how to debug the java. @elliotfrish and @cyberbrain did give enough explanations about that

Here is an explanation about why the openjdk 8 failed whereas the code was running fine on oracle jdk 8. The fact that I managed to launch the jar with openjdk8 on another VM also confirmed the issue was not on the jar itself but on the conf of the VM.

There was actually a font library missing on the VM. The installation of fontconfig.x86_64 and its dependencies solved the issue.