I am currently intern at telecominication company which is major one and also undergraduate student.I have lots of options sitting front.By know i know c,c++,c#,java languages on stand alone application side,on mobile side i trying to get into android world and also know php,mysql,asp.net and also java ee,spring on web side.But i really can not choose which side to go or focus,any suggestion from expreinced developers would be great for me.
Just pick one and run with it - they're all interesting and have a future.
If you can not choose — don't. Go for all of them until you know who you're in love with.
Just find a project that you find interesting (regardless of whether its standalone, mobile or web). And just work at it, you'll gain valuable experience not just in the specifics of whatever the project is aimed at, but also as a programmer in general, these skills will carry over into the other fields.
Really just find a project which is interesting to you, none of the types you mention are going anywhere, so it shouldn't matter which you choose.
There is no right answer to this.
That being said, I prefer Java web apps. Why? Because I am comfortable writing them. To me they are straight forward, easy to read, easy to maintain (if done right).
I like writing in Java because to me:
for(int i = 0 ; i < 10 ; i++) sum += i*i;
Is more intuitive than: (if I even got that right for python) sum(i*i for i in range(10))
Sure, it's more lines of code, but personally I find it easier to read and maintain. Programming in perl, ruby and python takes the same kind of person that actually enjoys writing complex regular expressions. At least that's the way I see it.
Don't guide yourself by market opportunities, ask yourself what do you want to bring to the world.
What you do as a developer must reflect what you believe in. I know many people that don't like the idea of applications running on the web and work with rails. I don't think they'll be happy for a long time in their jobs.
Once you know what you want to do, it will be clear if you should study Java, C#, C/C++, ruby, python, perl or whathever language you wonder about.
As Orson Welles said, "Always have a vision. Why spend your life making other people's dreams?"