The spec on CachedRowSet.createShared should clearly say that shared rowset instance is ready for use immediately after method return.

One of the JSR114 implementors requires to run method close() after method
createShared() in order to 'detaching' the original rowset from the shared.
Sun's rowset implementation does not require such behavior.
The following TCK tests fail because of this issue:
api/javax_sql/rowset/impl/CachedRowSet/index.html#CachedRowSet[createSharedTest]
api/javax_sql/rowset/impl/FilteredRowSet/index.html#FilteredRowSet[createSharedTest]
api/javax_sql/rowset/impl/JoinRowSet/index.html#JoinRowSet[createSharedTest]
api/javax_sql/rowset/impl/WebRowSet/index.html#WebRowSetcloseTest[createSharedTest]