Thank you for Skipper_Joe's answer!
The MDS I referring is included in JDE 4.1.0, which can use it to access the network!
I'm doing network development on BlackBerry, and find 4.2.1 can not visit the network(for example visit website ),maybe I do the wrong configure. And I find that JDE 4.1.0 can do all of these, so I always do development on JDE 4.1.0.
Because I am a newer , I don't know which one is suitable for learner or which one is professional.
So do you mean I should turn to study Eclipce or else for a newer?Thank you!