title: How to get a value from a subjframe back to the first jframe
body: <p>In java, Say I have a JFrame (say JFrame2) which is created by clicking a button on the first Jframe (JFrame1). 
  How do I get a selected value from the second (Jframe2) back to the first one without creating a new instance of the first frame (Jframe1).</p>
  
  <p>i.e I want to make Jframe2 a subform of JFrame1. Just the way a <code>JOptionFrame.showMessageDialog()</code> would return a value.</p>