Update CI to JDK 9
Update CI to JDK 9

Siedlerchr/jabref,zellerdev/jabref,Siedlerchr/jabref,sauliusg/jabref,sauliusg/jabref,sauliusg/jabref,JabRef/jabref,JabRef/jabref,JabRef/jabref,zellerdev/jabref,Siedlerchr/jabref,Siedlerchr/jabref,JabRef/jabref,zellerdev/jabref,zellerdev/jabref,sauliusg/jabref,zellerdev/jabref