Java2 is just a newer version of Java.
Actually Java2 is missleading, Java v0.0 to Java v1.2 (I'm pretty sure) are considered Java1
Java v1.3 to Java v1.5.0 are considered Java2. The only reason they say "Java 2" is because the changes were so dramatic, it was like a whole new language.
I suggest going to amazon.com or ebay and buying a used book about Java v1.4.2 or later. Anything before that will be outdated. It won't be a lost cause, but it will serve you much better to get a new book.
And a used book (which is all I buy, and I've never had a bad book. All of them are like new) will cost you anywhere from $2 to $20 (USD).
I pay about $5 on average for all my books, and they're in perfect condition, and are all updated.
My 2 cents.