title: Unable to export runnable jar, launch configuration grayed out
body: <p>I am not able to figure out how to export a runnable jar in eclipse.</p>
  
  <p>I have a java project (project A) (written by someone else) which when imported in Eclipse, I can click <code>Build Project</code> and it will create a <code>projectName.jar</code> file under <code>bin/</code> directory. That jar file contains binary *.class files.</p>
  
  <p>This jar file is added as external library for another java project (project B) which I want to debug. But because all the class files are binary I'm not able to do line-by-line debugging when classes from projectA are called.</p>
  
  <p>I tried exporting <code>Runnable Jar</code> in Eclipse, for that I have to select a <code>Launch Configuration</code>. But there is no <code>main</code> class in project A. (I recursively grepped for <code>main</code> and didn't find any).</p>
  
  <p>What can I do to export jar of project A that contains respective source code also (which will be used in line-by-line debugging)?</p>