After updating to the latest Java version on Mac OS X, I now get this exception when using JFreeChart:

Exception in thread "main" java.lang.NoClassDefFoundError: apple/laf/CoreUIControl

Not sure what the actual problem is, but at least one other developer has run into it:

The effect is similar to that described in this issue:

This is almost certainly Apple's bug to fix, but maybe it is a good time to re-evaluate your reliance on UIManager to establish the default background color.  ;-)