Nimbus Look-and-Feel in JDK 7
By Henrik Stahl on Nov 08, 2010
The Nimbus look-and-feel for Swing was introduced in JDK 6u10 as a replacement for the old Metal LoF. With JDK 7, Nimbus will be moved from an Oracle-proprietary extension (com.sun.java.swing) to a standard API (javax.swing) so that it becomes a true first class Swing citizen.
However, we do not plan to make it the default (platform-independent) LoF. Nimbus looks much better than Metal, so this is very tempting, but we have concluded that it would break too many existing applications. We are aware that this goes against the desire expressed in previous polls and we hope that the community can forgive us for wanting to err on the side of caution.
We recommend that you explicitly choose Nimbus in your source code (or configuration) to ensure that your applications look really good with JDK 7. For more info, see the tutorial.