[This](http://stackoverflow.com/a/6502320/895245) answer was deleted because of link rot. Copy paste for those who can't see it:

>Yes, see [os::javaTimeMillis][1] in `/src/os/solaris/vm/os_solaris.cpp` to see the Solaris implementation for instance. There are a few layers of wrappers to get there though, see [JVM_CurrentTimeMillis][2] in `/src/share/vm/prims/jvm.cpp`

[1]: http://hg.openjdk.java.net/jdk7/hotspot/hotspot/file/9b0ca45cd756/src/os/solaris/vm/os_solaris.cpp

[2]: http://hg.openjdk.java.net/jdk7/hotspot/hotspot/file/9b0ca45cd756/src/share/vm/prims/jvm.cpp


Although it is true that the links were an important part of the answer (they point to the online JDK source browser), it also contained other useful information, and anyone who saw the rotten URL would be able to find the updated link themselves.

The result is that new users with <10k rep lose useful information.