Is Java installed on my computer?

Most recent versions of Windows, MacOSX, Linux and Solaris will have Java installed already.

To check for sure, type the instruction java -version on a terminal or similar application and press return/enter. If you have Java installed you will get an answer with the version installed on your computer shown in quotes.

Windows

Use a program like MS_DOS prompt or Command Prompt

These can be found in: Programs -> Accessories -> Command Prompt or Programs -> MS-DOS Prompt

The computer in the above example has Java 1.6 (Java 6) installed.

MacOSX

Use the program called Terminal.

It can be found in: Applications -> Utilities ->Terminal

The computer in the above example has Java 1.5 (Java 5) installed.