Hmm, i guess you should know basics of programming. If you did not learn basic programming before, i think having a friend or teacher will help you to pass initial obstacles in your road. Since you are not aware of programming, everything might look strange at that stage.
If you have basic programming, object-oriented-programming might be difficult for you to understand. Most of the Java books has some introduction section for object-oriented programming. That might be enough but if you are having difficulty then you can have another book for object-oriented programming to help you.
Other than these, having a couple of books, reading them and developing projects or contributing existing projects are needed. In addition to these, you can ask problems you have faced with to us. We will try to answer your questions..
And after a point, you will see that you are solving your problems yourself in Java.
If you are already an experienced programmer in another language, then just buy a good book and learn it
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Here is a good book i suggest:
Amazon.com: Head First Java, 2nd Edition: Books: Kathy Sierra,Bert Bates