public void flush() throws IOException {
  flushBuffer();
  _outputStream.flush();
}

public void flush ( ) throws IOException { flushBuffer ( ) ; _outputStream . flush ( ) ; }
flushes the stream . if the stream has saved any characters from the various write ( ) methods in a buffer , write them immediately to their intended destination . then , if that destination is another character or byte stream , flush it . thus one flush ( ) invocation will flush all the buffers in a chain of writers and outputstreams .
