A Core 2 Duo should not lag running an IDE. I ran Visual 2008 on a Core 2 Duo with Sql Server running and it had 4GB of RAM.
Netbeans and almost every other Java IDE at the time was one of my major turn offs about using Java compared to using .Net + Visual Studio.
In fact, I still use the same Core 2 Duo 2.66Ghz with 4GB of RAM running Windows 10 as my Plex Server and it can transcode up to two streams simultaneously. I'll still use it interactively when I'm working from home and I'm mindlessly browsing the web while I am waiting on something.
