Download and install Java JDK in your computer.
Set up the path in Windows 7 for use your JDK, the JDK contains the Java applications for run and compile java programs in a folder called “bin”.
Go to control panel -> system -> advance system settings -> environment variables -> new in User Variables.
The name of the variable must be “path” and the next line the location of the jdk, for example “C:Program FilesJavajdk1.6.0_25bin;”