Where are all my Java VMs installed in ubuntu?

Question

In my Ubuntu 8.04 'Other' menu, it has 'OpenJDK Java 6 Runtime', 'Sun Java 5.0 Runtime' , 'Sun Java 6 Runtime'.

Can you please tell me where are these actually installed? I can only fine 1, the OpenJDK :

$ which java /usr/bin/java

$ java -version java version "1.6.0_0" OpenJDK Runtime Environment (build 1.6.0_0-b11) OpenJDK Server VM (build 1.6.0_0-b11, mixed mode)

How can I find the others?

Thank you.

Answer 1

try in terminal whereis java

It is probably a simlink located in /usr/bin, you can check what real file is the simlink pointing to easily, for example using ls:

ls -l /usr/bin/java

Answer 2

Most modern Linux distros uses update-alternatives to manage the various java installations. You can see which ones are currently available with:

update-alternatives --list java

And change the active alternative with:

sudo update-alternatives --config java

See man 8 update-alternatives for more details.

Answer 3

You can list all the files belonging to a package with

dpkg-query --listfiles PACKAGE

The package name might be sun-java6-jdk or sun-java6-bin. But you can easily find out the package name with synaptic.

Answer 4

I forget exactly on Ubuntu, I think they get stuck in either /usr/java or /usr/lib/java, at any rate, locate java|grep usr should give you an idea of where it's at.

Answer 5

The jre/jdk's are always installed under /usr/jvm. libraries (jar files) for extra packages are installed in /usr/share/java.