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Gentoo Java 1.5 FAQ


1.  Why was Java 1.5 hard-masked for so long?

Java 1.5 was hard masked forever because there were a number of issues which made it unsafe to use a 1.5 JDK as your system VM.

The first issue with Java 1.5 was backwards compatibility. If you compile packages with a 1.5 JDK, the default behavior is that the compiled classes can only be used in a 1.5 or above VM.

The other significant issue is that there are packages which are not compatible with JDK 1.5, as they currently exist in the portage tree. For example, several abstract classes and interfaces now have new abstract methods in 1.5. This means that packages would need to be patched to override these abstract methods. Failing that, you could also try using 1.4 to compile the offending package. However, due to the backwards compatibility problem mentioned above, you wouldn't be able to use external libraries, because they were compiled only for 1.5.

2.  What is the status of Java 1.5?

The good news is that work is that support for 1.5 is here!

To begin using it, you will need to follow the upgrade guide.

The Java documentation has been updated for the usage of this new system, and is available at:

Additional material can be found at the following, under the 'Migration' section:


Page updated July 24, 2006

Summary: This FAQ covers issues related to Java 1.5 support on Gentoo.

Joshua Nichols

Karl Trygve Kalleberg

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