Question

I know that, as of Java 1.5, one can add a component to a JFrame like this:

myFrame.add(myButton);

instead of:

myFrame.getContentPane().add(myButton);

Why wasn’t this always the case?

Answer 1

As is spelled out in the JFrame API, both do the same thing: add a component to the contentPane. It’s just recently (Java 1.5 perhaps?) Swing added the syntactic sugar/convenience method to allow you to make this call directly on the JFrame (or any other Swing top-level container), but you’re still adding to the contentPane. Same for remove(...) and setLayout(...) This becomes all too clear if you try to set the background color of the JFrame via myJFrame.setBackground(Color.green); and nothing happens. It is for this reason, I’m not too happy with this change. That and also because I must be an old curmudgeon.