title: Solution to extend multiple classes
body: <p>Let's say I have Class A and B that differ except on using color variables.
  Both classes already extend the JPanel Class so I cannot extend a new class with the color variables in it. I then thought I could make class C (with the colors in it) an interface. But it's not allowed to have attributes in an interface.</p>
  
  <p>Any idea how I can still use the colors in an external class for both Class A + B?</p>
  
  <p>The thought:</p>
  
  <p>Class A - Uses the colors<br>
  Class B - Uses the colors<br>
  Class C - Has the colors.</p>