public InputStreamReader(InputStream in,Charset cs){
  super(in);
  if (cs == null)   throw new NullPointerException("charset");
  sd=StreamDecoder.forInputStreamReader(in,this,cs);
}

public InputStreamReader ( InputStream in , Charset cs ) { super ( in ) ; if ( cs == null ) throw new NullPointerException ( "charset" ) ; sd = StreamDecoder . forInputStreamReader ( in , this , cs ) ; }
creates an inputstreamreader that uses the given charset .
