For downloading J2SE Runtime Environment enter " java.sun.com " in address bar and then press enter.

Click on Downloads

Following page is open
Click on java SE(JDK)6

In part " JRE 6 Update 16 " click on download to start downloading

In download page select accept to accept License Agreement
This page offers files for different platforms, base on you'r platform select appropriate file

Press on save to saved downloading file.

Specified the location want to save file

To learn how installing download file click here How to install J2SE Runtime Environment.