I bet you will get offers sooner or later. hope the offer comes

Java/C++/SQL/J2ME/J2EE skills with 4年工作經驗 will get you a lot of chances for the interviews.

what you should do is: make sure where are the problems for your job hunting.
--is the resume that attractive?
--why 有的麵試失敗了，有的麵試沒有回音?
the interview questions are well-prepared?
is your english smooth?
or did you look boring for the interviewer:)
etc...

good luck!