I have a plugin project. When i debug this as an eclipse application, in the 2nd eclipse that opens, I want to open Project explorer window. As soon as I click on the button
You should add the -XX:MaxPermSize=256m
or 512m to the Window>Preferences>Java>Installed JREs
preference page. Edit a JRE and add it to the Default VM arguments tab.
The eclipse native launcher uses the eclipse.ini to add extra permgen arguments to Oracle JVMs, but that information is not used during runtime launching.