The Java language is very complex and detail oriented. Many resources are available to get you started down the path to learning Java. I personally recommend using the Java Tutorials provided by Sun, which has been taken over by Oracle. These tutorials are free and easy to read through. The articles will give you a good foundation based on the standards of the people who maintain the language. As far as books are concerned, I recommend using Effective Java, Head First Java, Core Java, and/or any Deitel books. All of these books have well defined and easy to follow examples.
After reading a few books and getting your feet wet, you may be at a loss for what to do next. Well, the good news is there are plenty of communities on the web were people are more than willing to lend a helping hand. Communities such as Dream in Code and stackoverflow are great places to go to find like minded individuals. Finally, if you are short on ideas about what to program, I suggest going to Mindprod: Java Student Projects and seeing if any of these ideas meet your fancy; there also might be some money in it for you.
So, that’s a good place to start down the path for becoming a Java Developer.