Hello,
I have learned core Java and wanted to apply it through some project. I also wanted to know, what is the importance of certification courses like SCJP? Is it necessary to get certified? What languages and techonogies are in demand now (or will be in the future) so that it could make my curriculum vitae look heavy and help me in getting placements in companies like Microsoft, IBM, Google, Yahoo!, etc.?
Experience is the only thing which have market everywhere and anytime. Every technology have its own importance.
No one is greater than other. Choose any language and try to get knowledge and improve skills. Certification is always good. Its like some proof to show that you know something.
Just select the language as you like to work in web or system side , data base or anything else.
Never think about those 3 companies always. There are hundreds and thousands of better companies than those which offer better work