I have always felt that the official Java document is a bit messy, recently deliberately collated, for reference only.
Entrance
Oracle Official Documentation Portal: http://docs.oracle.com/. The subordinate page this side only organizes the Java EE and the javase document.
Java EE
Java EE document entry: http://docs.oracle.com/javaee/. Downlevel pages have Java EE-related APIs and tutorial documentation:
- http://docs.oracle.com/javaee/7/api/
- http://docs.oracle.com/javaee/7/tutorial/
Javase
Javase Document Entry: http://docs.oracle.com/javase/, it jumps to the current version and is now http://docs.oracle.com/javase/8/. The subordinate pages are:
- http://docs.oracle.com/javase/specs/
- http://docs.oracle.com/javase/tutorial/
There's a specific version of the document, and we'll just look at Javase 8,
- http://docs.oracle.com/javase/6/docs/
- http://docs.oracle.com/javase/7/docs/
- http://docs.oracle.com/javase/8/docs/
javase/8/docs/
There are mainly 3 subordinate pages,
- http://docs.oracle.com/javase/8/docs/api/
- http://docs.oracle.com/javase/8/docs/technotes/tools/
- http://docs.oracle.com/javase/8/docs/technotes/guides/
Tools describes the JDK-related tool, 2 sub-pages per platform,
- http://docs.oracle.com/javase/8/docs/technotes/tools/unix/
- http://docs.oracle.com/javase/8/docs/technotes/tools/windows/
Guides introduced some technical points of javase, such as RMI,JPDA,JVMTI,ATTACH,JVM and so on.
- Http://docs.oracle.com/javase/8/docs/technotes/guides/rmi
- http://docs.oracle.com/javase/8/docs/technotes/guides/jpda/
- http://docs.oracle.com/javase/8/docs/technotes/guides/jvmti/
- http://docs.oracle.com/javase/8/docs/technotes/guides/attach/
- http://docs.oracle.com/javase/8/docs/technotes/guides/vm/
There's another entrance,
- Description of Java Conceptual Diagram
technotes/guides/vm/
There is still too little data in this JVM documentation, and then I extracted two pages from Otn,
- Java SE at a Glance
- Java SE HotSpot at a Glance
Find the entrance to HOTSPOTVM related documents.
Of course, to find HOTSPOTVM documents, must get OPENJDK home, mainly have the following two entrance,
- http://openjdk.java.net/groups/hotspot/
- Https://wiki.openjdk.java.net/display/HotSpot/Main
VM Options
Two more virtual machine options related documents, easy to use when querying.
- Http://www.oracle.com/technetwork/java/javase/tech/vmoptions-jsp-140102.html
- Http://docs.oracle.com/javase/8/docs/technotes/tools/unix/java.html#CBBIJCHG
There are so many official documents that you don't have to buy any more books to chew on. ^_^
Official Java Document Index