How to clone the OpenJDK Java 8 repository?
The repository is linked on http://openjdk.java.net/. Clone it and execute theget_source.sh
script.
$ hg clone http://hg.openjdk.java.net/jdk8/jdk8
$ cd jdk8 && sh get_source.sh
A guide to the OpenJDK repositories and a How to contribute are available, too.
Have a look at the README of the version you want to clone.
After doing what another answer said:
hg clone http://hg.openjdk.java.net/jdk8/jdk8
you also need to run:
sh get_source.sh
to actually clone most of the source code, which is split into multiple sub-repositories.
Related: How can I checkout the OpenJDK from the mercurial repository?