question: protected void parseHeaderLine ( String line ) throws IOException { int len = 2 ; int n = line . indexOf ( ": " ) ; if ( n == - 1 ) { len = 1 ; n = line . indexOf ( ':' ) ; if ( n == - 1 ) return ; } String key = line . substring ( 0 , n ) ; String val = line . substring ( n + len ) ; List < String > list = headers . get ( key ) ; if ( list != null ) { list . add ( val ) ; } else { list = new ArrayList < String > ( ) ; list . add ( val ) ; headers . put ( key , list ) ; } }
target:  Reads one response header line and adds it to the headers map.