java.security.PrincipalWLSGroupImplpublic interface WLSGroup
extends java.security.Principal
WLSGroup interface is a marker interface used to signify that a
 principal represents a WebLogic Server group. Therefore, any principal that is going 
 to represent a WebLogic Server group should implement this interface.
 If you want to get all the groups a user belongs to, you should get all 
 principals of this type. Alternatively, the best way to find out if a user
 is in a group is to use the
 SubjectUtils.isUserInGroup method.