I want java and I have leopard. I can't find any version of java on this computer.

You forgot to tell us what Mac you have, but if it came with Leopard or an earlier version of OS X, then it would have had Java preinstalled.

Update 10, 29 June 2011 - This release updates J2SE 5.0 to 1.5.0_30, and updates Java SE 6 to 1.6.0_26. J2SE 1.4.2 is no longer being updated to fix bugs or security issues and remains disabled by default in this update. Support for out-of-process Java applets on Mac OS X 10.5 Leopard has been removed with this update.

This release is only for Intel Macs running versions of Mac OS X 10.5. http://support.apple.com/kb/DL1359

Note: Java 1.6 for Leopard is 64 bit only.

Is it maybe disabled in your browser, the opposite of these?

http://support.apple.com/kb/HT5241?viewlocale=en_US

http://support.google.com/chrome/bin/answer.py?hl=en-GB&answer=142064

http://support.mozilla.org/en-US/kb/How%20to%20turn%20off%20Java%20applets

Locate the version of Java that’s installed on your Mac OS X system.

1. Open the Utilities folder and run the Terminal application.

2. Type java -version and press Enter.

(space between java & -v important)

The version of Java that you have installed will then be displayed on the screen.