Even though the version name Java SE 6 Update 10 only indicates small bug fixes, Sun Microsystems has put Java's fat runtime environment on a strict diet, modularising and optimising it.
Sun wants to give users more incentive to use Java software on their desktops and applets in their browsers. The tried and tested Java VM is also the basis for the new JavaFX, a web technology with which Sun intends to compete with Flash and Silverlight in browsers.
The new installer initially only loads the required libraries from the net; only 4 to 5 MB are required to start an applet or a Swing application. The previous version still required just under 15 MB.
Nimbus, a new look & feel for Swing, adds a contemporary touch to Java applications. Sun also pointed out that that the new Java is considerably faster than it was before: startup time for Java programs has been reduced and a new pipeline connects Java directly to Direct3D in Windows allowing hardware graphics acceleration. Full details of the changes are given in the release notes for Java 6u10 and an earlier article from Sun on the alpha version of Java 6u10 explains the changes in more detail.