Just a super-quick simple tip to fix something that drove me mad.
I am not a power-user of Eclipse, in fact I rarely use it. When I do I tend to mess up the perspectives pretty quickly. To reset the layout...
Click on Window in the top nav, then click on Open Perspective, then click on Other, then click on Java EE (or you could use Java). Then click on Window again, and click on Reset Perspective.
