7009266: G1: assert(obj->is_oop_or_null(true )) failed: Error Summary: A referent object that is only weakly reachable at the start of concurrent marking but is re-attached to the strongly reachable object graph during marking may not be marked as live. This can cause the reference object to be processed prematurely and leave dangling pointers to the referent object. Implement a read barrier for the java.lang.ref.Reference::referent field by intrinsifying the Reference.get() method, and intercepting accesses though JNI, reflection, and Unsafe, so that when a non-null referent object is read it is also logged in an SATB buffer. Reviewed-by: kvn, iveresov, never, tonyp, dholmes

README:
  This file should be located at the top of the hotspot Mercurial repository.

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

  See ../README-builds.html for complete details on build machine requirements.

Simple Build Instructions:

    cd make && gnumake
     
  The files that will be imported into the jdk build will be in the "build"
  directory.