where can I learn the fundamentals of Java and how long will it take to learn?

In my next computer science class I will be learning Java, but I want to spend some time over the summer familiarizing myself with it and perhaps making my own applications.
Simply, what are some of the uses of Java, fundamentals of its structure, and what the kinds of things I could create with its programming?
and any introductory tutorials that explain concepts would be great

Try this site: http://www.java.com/en/download/faq/develop.xml
It’s pretty comprehensive.

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