When the Sun JDK is installed and used according to directions, it doesn't work as advertised: java, javac, appletviewer, or other tools fail to find core classes and generally don't work in expected ways. What's the problem?

Nathan Meyers

This is usually caused by having Kaffe installed on your system in addition to the Sun JDK - Kaffe's versions of java, javac, appletviewer and such do not support the full JDK1.2 spec, and may report missing classes or otherwise fail to run.

Make sure that the JDK's bin/ subdirectory appears in the path before the Kaffe executables (which usually live in /usr/bin). You may want to uninstall Kaffe entirely ("rpm -e kaffe" on Red Hat distros).

For further information on mixing Java environments on Linux, see this question.