Typos.
JUnit 4.
Prevent duplicate Permission or PermissionGroup objects from being created.
Merge branch 'master' into unique-Permission
Document that IllegalStateException will be thrown for a duplicate Permission or PermissionGroup.
Enforcing consistent synchronization of PermissionGroup.permissions.
change BuildStability message into more appropriate one
Merge branch 'unique-Permission' (#1444).
Merge pull request #1484 from ocadaruma/japanese-message

change BuildStability message into more appropriate one