code: protected final void setQWForFiles(final Writer writer) {
  		final SynchronizedCountingQuietWriter countingQuietWriter = new SynchronizedCountingQuietWriter(writer, super.getErrorHandler());
  		this.getProperties().setCountingQuietWriter(countingQuietWriter);
  		super.qw = countingQuietWriter;
  	}
docs: /*
  (non-Javadoc)
  
  @see org.apache.log4j.FileAppender#setQWForFiles(java.io.Writer)