These are in no particular order, but these are things that
all Java programmers should probably know.
- Who Invented Java, and when?
James Gosling, at Sun Labs, around 1992; the group was building a set-top box and started by "cleaning up" C++ and wound up with a new language and runtime. - What does Java stand for?
Java is not an acronym (not even Just Another Vague Acronym :-)). The language was first named Oak, after the tree outside James' window. The lawyers found a computer company called Oak so, legend has it, the gang went out to the local cafe to discuss names and wound up naming it Java; the "0xCafeBabe" magic number in the class files was named after the Cafe where the Java team used to go for coffee. - What is the JLS?
JLS is The Java Language Specification. Every developer should buy or download (free) this specification and read it, a bit at a time. - How do changes get into Java? JCP (Java Community Process).
 - Why is there no printf-like function in Java?
Actually there are! This was fixed in Java 5; see Java Cookbook (2nd Edition) Chapter 9. Java 5 (J2SE 1.5) includes printf (and scanf), String.format(), and lots more. - What is the GOF book?
The Gang Of Four book is entitled Design Patterns, by Erich Gamma, Richard Helm, Ralph Johnson and John Vlissides. This is a very good book. You should read it. Not when you're just learning Java, but when you've let it sink in for about six months. - What other Java book do I need?
 
- Most of the O'Reilly Java books.
 - Effective Java, by Joshua Bloch
 - Java Developer's Almanac
 - My Java Cookbook (see below)
 
 - What is the Java Cookbook?
That's my own book of Java recipes (for the programming language, not the coffee, but some bookstores still wind up listing it under Cooking). - What other Java sites do I need to know about?
 
- java.sun.com, Sun's main technology site
 - java.net, a collaborative site (run by Sun)
 - java.com, an advocacy/news site (run by Sun)
 - developer.java.sun.com, Sun's main developer site
 - www.javalobby.org, independent advocacy group
 - www.javaworld.com, Java news
 - www.theserverside.com, Java Review
 - http://www.darwinsys.com/java/, my own Java site
 
 - What else do I need to know?
 
 Everything! But nobody can know everything about Java - the subject
 is now too vast. Imagine somebody saying that they know everything
 about every single Microsoft product and technology. If someone like
 that calls me, I'm always out.