Java

Indian IT industry prefers B.Tech CSE/IT, MCA, BCA, B.Sc CS/IT graduates for technical roles. Therefore, you may face challenges in getting technical roles in IT companies. You are advised to do MCA for a meaningful IT career.

Java, for sure. If you know Java from deep you are an open weapon. Try to learn php, Python and Django language along with Java.
All the best.

Indian IT industry is slowly losing it's prime position because of global economical conditions and outcry against outsourcing. Creation of fresh jobs in the industry has reduced to single digit. Salary are stagnated for the last few years. Industry prefers B.Tech CSE/ IT and MCA graduates who are ready to be deployed on the projects easily without much effort. Therefore, you are advised to look for opportunities in mechanical engineering only.

Software development career is a better option for you as IT industry prefers ECE or EEE graduates for Hardware & Networking roles. You can start with Java certification. You may also do any RDBMS development certification so that you can get job in any Apps development company.

If you are a beginner try for 'Java in 21 days'. You can get an online copy of it for free.

Being a B.Com graduate with a Diploma in java, I expect a minimum of 10k per month. Assuming you have a very good knowledge in java, you can jump up to 40k in an year or so.

Advanced java is something which makes an application. Start learning advanced java, and platforms like hibernate, spring, bean, etc.