title: Java Swing set "actual" Frame size (inside)
body: <p>I have a JFrame which contains just one JPanel.
  I have tried setting the Panel's size and packing the frame, but that has no effect.</p>
  
  <p>If I set the JFrame's size, it will change the size so it includes the title bar and borders.
  How do I set the "actual size" so it doesn't include the title bar and borders?</p>
  
  <p>Example:</p>
  
  <p><img src="https://i.stack.imgur.com/PU93n.jpg" alt="Example"></p>
  
  <p>Thanks in advance, guys</p>