How to search snapshot in all streams using Java API

I know how to search snapshot in particular stream using Java API. How to search snapshot in all the streams using API. The below cod is for searching in a particular stream but how to search in all streams. If I comment the line criteria2.setExactName(stream_name); it shows snapshot not found error.
IWorkspaceSearchCriteria criteria2 = IWorkspaceSearchCriteria.FACTORY.newInstance();
criteria2.setKind( IWorkspaceSearchCriteria.STREAMS );
criteria2.setExactName(stream_name);
IWorkspaceSearchCriteria criteria2 = IWorkspaceSearchCriteria.FACTORY.newInstance();
criteria2.setKind( IWorkspaceSearchCriteria.STREAMS );
criteria2.setExactName(stream_name);