public InputStreamReader(InputStream in,String charsetName) throws UnsupportedEncodingException {
  super(in);
  if (charsetName == null)   throw new NullPointerException("charsetName");
  sd=StreamDecoder.forInputStreamReader(in,this,charsetName);
}

public InputStreamReader ( InputStream in , String charsetName ) throws UnsupportedEncodingException { super ( in ) ; if ( charsetName == null ) throw new NullPointerException ( "charsetName" ) ; sd = StreamDecoder . forInputStreamReader ( in , this , charsetName ) ; }
creates an inputstreamreader that uses the named charset .
