The Project Explorer view provides an integrated view of all project resources, including models of J2EE deployment descriptors, Java™ artifacts, resources, Web services, databases, and dynamic Web project artifacts.
You should use this view to work with your J2EE deployment descriptors and their content. You can view an enterprise application project and see all of the modules associated with it.
You can also filter what you see in the Project Explorer view to hide projects, folders, or files that you don't want to see. To enable or disable filters, click the Filters button from the drop-down menu at the top right corner of the view. For more information, see Filters in the Project Explorer view.
Alternately, you can filter what you see by showing or hiding working sets, groups of related resources or projects. See Working Sets.
The following image shows the Project Explorer view with a few projects: