Hmmm. Sounds like your Eclipse installation is mighty broken! The whole
raison d'etre of Eclipse is to support the "JDT", the powerful
Java editor and development tools.
But it is actually possible to download the "Eclipse platform" only, without the JDT; maybe that's what you've done. What you want instead is the "Eclipse platform SDK", which includes both the Eclipse platform itself as well as the JDT. Find your platform on
this page and download the appropriate distribution. Uninstall whatever you've got, install this, and out of the box, it will have a great Java editor.