I am having two JRE / SDK in my development environment, however it was necessary in my situation to set JAVA_HOME to 1.4.2, this is causing my eclipse IDE to stop running a
From the menu in the top.. Proceed as follows--
Project-->Properties--> Java Build Path--> Libraries--> JRE System Library.
Now click Edit . Select Alternate JRE. Click Installed JRE. Provide path to your other JDK. Then FINISH.
That's it.