Eclipse can be installed from the BOSS Linux repositories (click to view post on setting up BOSS Linux repositories and using synaptic), or you may choose to download Eclipse directly from the project’s website (click here). I would suggest using the project’s download page if you don’t mind downloading and installing the IDE manually, with Synaptic the process is pretty much automated. If you do choose to download from the Eclipse project’s download site be sure to choose the correct platform.
You can either use the repositories or the NetBeans IDE project’s download page(click to view). If you don’t already have JDK installed you can download the NetBeans IDE bundled with the JDK from here(click to view).
Both the IDEs need the Java Development Kit(JDK) to work. Also, there exist various various versions of both these IDEs for different progamming languages, so you can choose the version specific to the language you intend to program in.
Note: If you download Eclipse from the eclipse project’s website instead of installing it via Synaptic, remember to dowload JDK from Sun/Oracle’s website. It’ll probably be an executable bin file, you’ll need to run it and then copy the jre folder from the extracted JDK folder into eclipse.