Ask HN: Learning Java in 2010

Almost a month ago I read one "Ask HN" story, and debate, about Learning C++ in 2010 (<http://news.ycombinator.com/item?id=1119992>).

I was wondering the same about Java: It seems that the language and the ecosystem are taking off again and I am increasingly interested in Java projects (from Cassandra to Lucene and some other stuff from the Apache Incubator).

What should I read? How should I "practice" to avoid all the bad Java docs and programmers out there?