README:  This file should be located at the top of the OpenJDK Mercurial root  repository. This root repository will include a "make" directory,  and a Makefile for building the entire OpenJDK.  A full OpenJDK repository set (forest) should also include the following  6 nested repositories:    "jdk", "hotspot", "langtools", "corba", "jaxws"  and "jaxp".  There are also several source downloads for the jax* repositories that  will be needed.  This one root repository can be obtained with something like:    hg clonehttp://hg.openjdk.java.net/jdk7/jdk7 openjdk7  To make sure you have all the nested repositories, you can run:    cd openjdk7 && sh ./get_source.sh  (This is identical to using the Mercurial Forest Extension command    'hg fclonehttp://hg.openjdk.java.net/jdk7/jdk7 openjdk7').  People unfamiliar with Mercurial should read the first few chapters of  the Mercurial book:http://hgbook.red-bean.com/read/  Seehttp://openjdk.java.net/ for more information about the OpenJDK.Simple Build Instructions:    0. Get the necessary system software/packages installed on your system, seehttp://hg.openjdk.java.net/jdk7/build/raw-file/tip/README-builds.html  1. If you don't have a jdk6 installed, download and install a JDK 6 fromhttp://java.sun.com/javase/downloads/index.jsp     Set the environment variable ALT_BOOTDIR to the location of JDK 6.  2. Check the sanity of doing a build with your current system:       make sanity     See README-builds.html if you run into problems.    3. Do a complete build of the OpenJDK:       make all     The resulting JDK image should be found in build/*/j2sdk-imagewhere make is GNU make 3.81 or newer, /usr/bin/make on Linux usuallyis 3.81 or newer.Complete details are available in README-builds.html.