命令行如何获取openjdk7u/openjdk8u源码

最近在研究java虚拟机，在自己实现编译openjdk的时候如何通过命令行获取jdk的源码呢，在linux环境或者在win下的cygwin中，如下操作。

1. Install mercurial to /usr/bin.
2. Go to directory you want to download jdk8 sources.
3. Run there: hg clone http://hg.openjdk.java.net/jdk8u/jdk8u/
4. cd jdk8u/
5. chmod +x get_source.sh
6. LANG=C
7. ./get_source.sh
8. Make some coffee.
9. Read built-in README-builds.html (located in the jdk8u as stated in this example) in order to build sources from received data, depending on your system.
10. Enjoy.

如果想获取jdk7u呢，只需要将链接设置为http://hg.openjdk.java.net/jdk7u/jdk7u/