I have a decent experience with C++. I am a new linux user...just started with shellscripting. Besides this I am thinking of studing java (due to its platform independence). I am too confused about what to do, as the demand is changing too rapidly. I would like some help with what I should study.
Demand in the market is something to take into account, but if you look at the way Java developers have been in demand for a long time, I would not expect a big drop in the demand for Java skills in the near future.
As for what the future will bring: nobody knows. Maybe Google comes up with a programming language that will be wildly popular, maybe a guy in Botswana invents something fantastic. Programming languages have a way of becoming entrenched. Look at Cobol for instance. Not an especially popular language if you look at the blogosphere, but many people make a very decent living writing Cobol.
So in my opinion, demand is not changing all that rapidly. A language with the installed base of Java (or C#, or C++) is not going to disappear overnight.
I am too confused about what to do, as the demand is changing too rapidly.
I would say the demand for Java and C++ hasn't changed much in the last five years, and might not change for the next five years.
I am not interested in application development What sort of software development are you interested in.
I suggest you look at jobs in your area and see which ones interest you. Look at the skills they require and work on those.