In JDK b62 , there are two fix :

1) bug 6827026 ( http://monaco.sfbay/detail.jsf?cr=6827026 ) : Change default source and target level to 7 .

2) Changes in http://hg.openjdk.java.net/jdk7/jdk7/corba/rev/23f2c435056b
------------------

BOOTSTRAP_TARGET_LEVEL = 5
-TARGET_LEVEL = 6
+
+ifdef TARGET_CLASS_VERSION
+ TARGET_LEVEL = $(TARGET_CLASS_VERSION)
+else
+ TARGET_LEVEL = 6
+endif
-------------

These two changes make most of corba testcase failed because of the following error :
C:/Users/dtftest/AppData/Local/Temp/Work/JDK/corba/windows-i586/bin/rmic -classpath "Q:/comp/jsn/all_workspace/7_int/corba/rtm/lib/utils.jar;C:/Users/dtftest/AppData/Local/Temp/Work/exec/results-opteron002-09-06-30-10-07/workdir/dolphin;C:/Users/dtftest/AppData/Local/Temp/Work/JDK/corba/windows-i586/lib/tools.jar;Q:/comp/jsn/all_workspace/7_int/corba/rtm/lib/junit.jar" -iiop -keepgenerated -d C:/Users/dtftest/AppData/Local/Temp/Work/exec/results-opteron002-09-06-30-10-07/workdir/dolphin api.javax.rmi.PortableRemoteObject.ConnectImpl
error: Invalid class file format in C:\Users\dtftest\AppData\Local\Temp\Work\exec\results-opteron002-09-06-30-10-07\workdir\dolphin\api\javax\rmi\PortableRemoteObject\ConnectImpl.class. The major.minor version '51.0' is too recent for this tool to understand.
error: Class api.javax.rmi.PortableRemoteObject.ConnectImpl not found.

Please see detailed log file from : http://sqeweb.sfbay.sun.com/jsn/test_exec/corba_rerun/b62_winvista-i586_c1/results/corba_result/logs/api/javax/rmi/PortableRemoteObject.log

" The major.minor version '51.0' is too recent for this tool to understand." ,
51 is JDK 7 class version .So , rmic tool itself may come from an old JRE version .
I checked rmic class version , it shows jdk5 ( major version is 49 )
----------------
bash-3.00$ pwd
/java/re/jdk/7.0/promoted/all/b62/binaries/solaris-sparc/bin
bash-3.00$ javap -v -classpath .:../lib/tools.jar sun.rmi.rmic.iiop.Generator | grep major
  major version: 49
-----------------

Please update rmic to a jdk 7 class version, testcase may need updates as well.