title: JPanel in JFrame in NetBeans
body: <p>I have created a Java application (project) in NetBeans, in which I have designed a <code>JFrame</code> with menu bar, and different <code>JPanels</code>. I want these <code>JPanels</code> to appear inside the <code>JFrame</code> on action of different menu items, so that whenever the menu items are clicked different <code>JPanels</code> should appear inside the <code>JFrame</code>. I have designed both <code>JFrame</code> &amp; <code>JPanel</code> separately, but I couldn't link them together.</p>
  
  <p>Please help me out friends.</p>