ได้มาอีก 1 ละ จาก
http://java.com/en/download/faq/5000070400.xml=====================================
Can I remove older versions of the JRE after installing a newer version?
The latest version of the Java Runtime Environment (JRE) is always the recommended version as it contains updates and improvements to previous versions. The latest available version is always compatible with the older versions.
You can keep older versions of the JRE installed, in case you have an applet/application that still depends upon a previous version.
Note: You should report to the applet provider/developer about this dependability. They need to rectify their code in order to ensure compatibility with all JRE versions.
However, if you are running low on disk space, you can safely remove older versions of the JRE from your system following the instructions on:
Windows Java Runtime Environment uninstallation instructions page