I'm a bit late to the party, but I'd like to recommend eBuddy as an IT employer as well. They're usually hiring ops as well as developers for all sorts of platforms. They have an amazing office in the center of Amsterdam on Keizersgracht.
I can recommend both Backbase as well as eBuddy.
Backbase sells a portal-like product with a kickass front-end and is doing very well. The portals run on a Java backend.
eBuddy is the world's most succesful IM aggregator, with multi-network messengers on the web and every major mobile platform. Additionally, they are attacking the mobile messaging market with a new product called XMS. Lots of Java here too, both on the server as well as many mobile platforms.
I can recommend both companies because I worked there for a combined 8 years. Feel free to hit me up with a DM if you want more info.