This file should be located at the top of the OpenJDK Mercurial repository
  forest. This top or enclosing repository will include a "make" directory,
  and a Makefile at the very top of the repository.
  It should also include the 6 repositories: "jdk", "hotspot", "langtools",
  "corba", "jaxws"  and "jaxp".

  See http://openjdk.java.net/ for more information about the OpenJDK.

Simple Build Instructions:

  1. Download and install a JDK 6 from
     Set the environment variable ALT_BOOTDIR to the location of this JDK 6.

  2. Check the sanity of doing a build with the current machine:
       gnumake sanity
     See README-builds.html if you run into problems.
  3. Do a complete build of the jdk:
       gnumake all
     The resulting JDK image should be found in build/*/j2sdk-image

where gnumake is GNU make 3.78.1 or newer, /usr/bin/make on Linux and
/usr/sfw/bin/gmake or /opt/sfw/bin/gmake on Solaris.