title: Java decompiler plugin not working
body: <p>I have the JD-eclipse-plugin installed. I want to decompile the classes within a jar-file. So I select the jar-file within Project-Explorer and click Decompiler in the Menu. However both decompilers (JAD and JD-core) are greyed out. </p>
  
  <p>I also tried the steps shown in <a href="http://www.avajava.com/tutorials/lessons/how-do-i-decompile-java-classes-in-eclipse.html?page=2" rel="noreferrer">this blog on AVAJAVA Web Tutorials</a>. I guess the blog is a bit outdated, however I can see within Windows-->Preferences-->Java-->Decompiler that Jad is correctly set up. But there is no JD-eclipse found within Preferences-->General-->Editors-->File Associations as you can see in the following image.<a href="https://i.stack.imgur.com/apDPD.png" rel="noreferrer"><img src="https://i.stack.imgur.com/apDPD.png" alt="jd-eclipse-plugin"></a>. Now I right click the jar-file within Project-Explorer, but there is no such "Attach Source File".</p>
  
  <p>Did I miss anything to set up the plugin?</p>
  
  <p>EDIT: I´m using the following setup: Eclipse: Mars.1 Release (4.5.1); JadClipse 4.0.0; JDK 1.8</p>
  
  <p>EDIT2: Forgot to mention that I use Tomcat and want to dive into the libraries from <code>/WebContent/WEB-INF/lib</code>. This is not working, I cannot further collapse the jar-files. </p>