Sun is not the only vendor of Java

Many people who know about the Java programming language only know about the Sun implementation. But there are actually different vendors. There is:

IBM
HP
Apple
BEA
Blackdown

If you are programming Java on the AIX operating system (IBM's version of UNIX) then you would be using IBM Java. If you are programming Java on the HP-UX operating system (Hewlett-Packard's version of UNIX) then you would be using HP Java. Similarly, if you are programming Java on MacOS X then you are using Apple Java. BEA is not a creator of an operating system. They create a J2EE application server called WebLogic. It typically ships with the Sun version of Java and BEA's version of Java. The BEA version is called JRockit. Finally, Blackdown is an implementation associated with Linux.

The idea behind all these different implementations of Java is that they are better in some way. You should get better performance on your web applications if you use JRockit on the BEA WebLogic application server. If you are running Linux, the Blackdown implementation should give you better performance.

If you don't have access to HP-UX, AIX or MacOS X then you will not have the opportunity to use the OS manufacturers specific version. If you want though, you can download JRockit from BEA. Go to the BEA website, select Products then select JRockit. On the main JRockit page is an option to download JRockit for free. You can get Blackdown for free from the Blackdown website.