Enhance Java knowledge

Hi friends..
I am a mechanical engineering student..
I am very much interested in learning java.. i have been learning it for 4 months.. what kind of books can i read to enhance my java knowledge..
I will be attending the on campus interviews next year..

Only attending classes or reading books isnot enough to get a job. U need to practise hard .Knowledge in Java can only be enhanced by a lot of practise.