Closing Your Project
When you’ve created your application, you need to close any files you have open in Eclipse before you start your next application. You can do this by closing each file individually or by right-clicking the files and choosing Close All from the shortcut menu.
After you have closed all the files, you need to close the project itself. In Eclipse, in the Package Explorer, right-click the project and choose Close Project. By closing the project, you’re telling Eclipse that you currently don’t need to work with that project. This frees resources that Eclipse uses to track the project state, therefore speeding up your application.