test/tools/javah/compareTest/README

This directory contains a program for comparing the output of new javah against the
output of JDK 6 or other older versions of javah.

It cannot be run automatically because of the need for the older version of javah
to compare against.

The test works by scanning a jar file, such as rt.jar, looking for all files with
native methods.  It then runs both the old and new versions of javah on those
classes with native methods, and verifies that the results are character-for-character
identical.

To run the test, build langtools, then execute the script in the root langtools 
directory, providing the location of the JDK to be tested. The default is
/opt/jdk/1.6.0.
