here ur solution -> [Solved] JRE 8 gives "Wrong Java version" warning
"For JD 0.9.581 Java 1.6 is required. Such version was developed under Java 1.6, that's the reason why you have to useJava 1.6. If you use other java version, you could get some incompatibility problems (like that you have now).
If you want to keep/use Java 8 (1.8), I recomend to you upgrade to JD2."