I have been a C/C++ CAD software developer for more than 9 years (architectural CAD software developer for 7 years and modeler CAD software developer for 2 years after that). My new job involves Java technology. My IDE of choice was Eclipse, although I tried NetBeans and it is also a great tool.
It really helps if you increase the Java Virtual Machine memory usage related arguments in the eclipse.ini file. But I want to tell you what can extremely slow down Eclipse: the Virus Scanner. Why? Because in Java technology jar files (and ear files, war files, etc) are all actually PKZIP compressed data. This is very good for saving disk space. For the same reason, plus the ability to cloak an evil code a little made malware writers to often deliver their bad payload in compressed form also. Because of that Virus Scanners peek into the file, see the PKZIP magic number (“PKxy”), and they uncompress them and scan their content. This behavior can slow down Eclipse so much that it can become unusable. The only thing we can do against that (besides using Linux) is to find the option of “scanning compressed files” in your virus scanner and turn it off. It is important to understand that with this we decrease the defense of our system. Also important to note that turn off the scanning only for packed files.