When Microsoft and Novell announced they are collaborating, I did not think much of it. I already figured Microsoft was not going to threaten Novell’s Mono project, which is a clone of the Microsoft .NET framework than runs on Linux, Windows, and Mac OS. If the Mono project did not exist, I probably would not use .NET, and only use Java or other technologies for software development.
But now that Sun has announced that Java is now released under a GPL license, it makes more sense. See these notes by Miguel de Icaza, the leader of the Mono project, as well as these posts reacting to the Microsoft-Novell announcement.
You see this sort of thing in the tech industry all the time. Such as Microsoft lowering the price of the Xbox 360 before the release of the Playstation 3 and Nintendo Wii.
Now that Java has a GPL license, Linux distributions that typically only bundle GPL or other open licensed software in their distributions, such as Debian or Ubuntu, can now include Java as well. If you want to create a commercial Java application that uses java libraries, you may still do so thanks to the classpath exception to the GPL license.
But also the good news is that perhaps now open source clones of Java such as IKVM (which lets java applications run in the .NET framework) might be able to include the Swing GUI framework as well. This means you could have a Java Swing application run in either JVM (java) or CLR (.NET, Mono) runtimes.