Hi Soban,
I will answer your question in this way :
If I was an employer and I had to choose between two guys who have the same
Java experience but one of them has also a Java certification, for sure I would choose the guy who has the experience plus the Java certification.
By the employer point of view it's an extra guarantee that the professional who is beeing hired has a solid Java skill set.
Of course a Java certification does not guarantee that you will get a new GOOOOD job immediately, but it's always a good start.
If you are currently working on J2ME platform and you're planning to migrate to J2EE platform, I full recommend you start to get prepared to write the SCJP exam, which is the pre-requisite for all specialist certifications, and then get prepared to write any of J2EE specialist certifications (SCWCD, SCBCD, SCDJWS &
SCEA).
On the other hand I would like to advice you to don't underestimate the J2ME platform which you already have some experience.
Just to give you an idea, I'm from Brazil and here there's a large demand for such kind of professionals. Many companies have been instaled here such as Motorola, Nokia, Sony, Samsung, Siemens, LG, Pioneer and many others. All these companies produce mobile devices and even in Brazil, where there's a large Java community, it's hard to find certified professionals available in the market just because head hunters are always looking for these guys.
I have a friend who works in Australia and he told me that the same situation is happening there
So there's also a very good marked for such kind of J2ME professionals.
Hope that helps.