question: public void addRequestProperty ( String key , String value ) { if ( connected ) throw new IllegalStateException ( "Already connected" ) ; if ( key == null ) throw new NullPointerException ( "key is null" ) ; if ( requests == null ) requests = new MessageHeader ( ) ; requests . add ( key , value ) ; }
target:  Adds a general request property specified by a key-value pair.  This method will not overwrite existing values associated with the same key.