Suitable yes in the sense that it is above the "minimum system requirements". I've ran (older) versions of Eclipse and J2EE on much slower machines. I still recoil when I think of the time I tried to build distributed Eclipse plug-ins on an IBM T20.
Are you going to enjoy it and be very productive on it? I would bet not. You probably want more cores, more memory, etc. Developers are also prone to loss of concentration, so an added delay when switching windows, starting debugs, etc. will affect your performance.
In addition, I would highly recommend against trying to do full-time dev on a 13" screen. If you have to use your laptop screen, go with at least 15" with a decent resolution. IDEs require resolution these days because of the sidebars.
For about the same cost you can get a 15" MBP, better bang for the money. Core i5 in the new MBPs is also better structured for multithreading, IMHO, than the core 2 duos.