Sometimes it’s very necessary to notify/show confirmation the user before exiting the whole application.

So, for displaying the confirmation in RCP application we need to either override

boolean org.eclipse.ui.application.WorkbenchWindowAdvisor.preWindowShellClose()
 
OR
 
boolean org.eclipse.ui.application.WorkbenchAdvisor.preShutdown()

The return value of the above functions determines wheather to close the application or not, which is in default true.
Example:

public class ApplicationWorkbenchWindowAdvisor extends WorkbenchWindowAdvisor {
    .....................
    .....................
    
    @Override
    public boolean preWindowShellClose() {
        boolean result = false;
        // custom dialog code goes here. 
        // And the variable result is updated by the choice of the dialog. 
        return result;
    }
    ..................
    ..................
}