If you've installed java, and are getting a "java: command not found" message when trying to run java, it probably isn't located in your path.

At prompt, type 'echo $PATH' to show you your path(s). in order to execute something simply by typing it's name into the prompt, the executable file has to be in one of the path folders, or you must add that folder to your user's path.

Alternatively, you can launch java by using the full command:

/usr/java/jre1.3.1/bin/java (or wherever your java is insatlled in, i can't remember what the exact path is). So let's say you wanted to run the RunLime file from the prompt, you would open a prompt window and:

$ cd /usr/local/LimeWire (or wherever you insatlled limewire to)
$ /usr/java/jre1.3.1/bin/java -cp . RunLime

This should open LimeWire for you.