question: private synchronized void enumerateStringProperties ( Hashtable < String , String > h ) { if ( defaults != null ) { defaults . enumerateStringProperties ( h ) ; } for ( Enumeration < ? > e = keys ( ) ; e . hasMoreElements ( ) ; ) { Object k = e . nextElement ( ) ; Object v = get ( k ) ; if ( k instanceof String && v instanceof String ) { h . put ( ( String ) k , ( String ) v ) ; } } }
target:  Enumerates all key/value pairs in the specified hashtable and omits the property if the key or value is not a string.