It seems odd that when I left click a file in the project explorer it opens with gedit. Also, I found that if I drag the file over to the right it opens as it should, BUT the .java file has no color syntax and no intelli-sense!?
You need to install the eclipse package under synaptic package manager. Eclipse from the Ubunutu software center only installs the bare-essentials, and includes no java editor/jdk tools (ie: Java Perspective).