title: How to extract classes from .jar file?
body: <p>I have .jar file. I tried running command <em>jar xf my.jar</em> it gave nothing. I tried using JD GUI, but it gave me this message: <em>Invalid input file '/home/hey/Desktop/my.jar'.</em> </p>
  
  <p>Does it mean I can't extract classes from this .jar file?</p>