Specialization

#webdev #java #php #android

Hello guys,
What do you think about Specialization?
In my case, I'm so confused,i don't know if i should learn some of advanced things in web development, desktop apps development, and android apps development ...
Or Should Focus on one Programming language, or ... really I'm in bad situation,
Btw i love Java.
Any help or opinions will be perfect.
Thank you