[7u10] Request for approval for CR 7181320 - javac NullPointerException for switch labels with cast to String expressions

[Joe Darcy]

Hello,

Please consider for 7u10 a backport of the fix for
7181320: javac NullPointerException for switch labels with cast to 
String expressions
    http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=7181320

from JDK 8:

    http://hg.openjdk.java.net/jdk8/tl/langtools/rev/464f52f59f7d

The essence of the fix is to more uniformly preserve constant value 
information for string expressions so that the code generation for the 
string-in-switch statement can simply extract the constant value from 
the corresponding expression.

Thanks,

-Joe