I think I have the exact same dell!
On my website,
www.scja.com, I have a number of Java tutorials on how to create a Java file, compile it, and run it using javac. All of those tutorials were done on a Dell Latitude laptop with 256 megs of ram, and a 1.6Ghz processor. You can look at the tutorials and see that the performance is fast with just the SDK.
I will also be installing Eclipse and doing some more Java tutorials.
Now, eventually I will be installing
Tomcat and doing some simple
Servlet and JSPs. At that point, the 256 megs will definitely become too small.
Max out the memory on that machine - I think the max is 512, and don't install too many other programs on your OS - that'll bog it down in a hurry. But, I've got proof that you can get
SCJA and SCJP certified with that little laptop alone!
Cheers!
-Cameron McKenzie