Go through the JPanel constructors; there is one with a boolean parameter. All you have to do is pass true to that.
I am not certain that is the correct solution, but double-buffering is the first thing I would try.
Joined: Oct 13, 2005
It would seem to suggest that missing out the boolean flag will give it a double buffer, if you look at the JPanel ←link documentation. But it is still worth a rty.