How do I enable Java to do JNLP in Safari?
Quick and easy solution is to utilize an alternate browser. I had a similar issue with a Keyboard Video Mouse switch that required Java in order to initiate a JNLP (Java Web Start) session. After installing various versions of Java (1.6, 1.7, etc.) (O.S. is Mountain Lion) and trying to start a JNLP session in Safari (Version 6.0.5, [8536.30.1]) would see the efforts subsequently fail. I installed Google Chrome (Version 28.0.1500.71) and tried to initiate a JNLP session and it worked fine. Firefox may or may not work equally as well but I did not test beyond Google Chrome.