title: jar file doesn't open upon double click
body: <p>When I double click the jar file, the GUI program doesn't start by itself. Instead I have to open the Command prompt and then type <code>java -jar abc.jar</code> and only then it starts up. Why is that? What do I need to do to avoid this?</p>
  
  <p>Is it that I have some problem with the default jar file opener? What should be the jar file opener?</p>