Which courses should I learn in I.T companies?
If you have joined big IT company, you should look for the knowledge center on your company's internal portal. Many companies have their own learning tracks and you can choose any course you want.
For mechanical engineers, familiarity with C and C++ is a must and then you can learn Java as well. But you should talk to your managers about which domains or technologies are relevant to your job profile so that they can guide you properly.