Have to set up IDE for Java again, any hints?

[gerrit]

Hello
I've been trying to fix a bug in the Libreoffice Base reportbuilder, and 
to push the bugfix I deleted some stuff from my libreoffice folder that 
had nothing to do with my changes. now I found bugs in my bugfix and my 
carefully hacked together eclipse fails to read the sources again wich 
it barely did before. I was unable to find the Instructions I need 
online. There was only c++ setups, no java, and if there was java, it 
was to create my own plugin wich i'm also not doing. Can someone please 
show me instructions on how to easily and correctly setup any opensource 
IDE on Linux to debug the reportbuilder?
Greetings,
Gerrit Großkopf