Windows上でlog4jを使用した所UTF-8で出力されない

import java.io.IOException;
import java.io.Writer;

import org.apache.log4j.RollingFileAppender;
import org.apache.log4j.helpers.CountingQuietWriter;
import org.apache.log4j.spi.LoggingEvent;
import org.apache.log4j.Layout;

public class I18nRollingFileAppender extends RollingFileAppender {
	public I18nRollingFileAppender() {
		super();
	}
	public I18nRollingFileAppender(Layout layout, String filename, 
		boolean append, String encoding) throws IOException {
		this.encoding = encoding;
		this.layout = layout;
		this.setFile(filename, append, false, bufferSize);
	}
	public I18nRollingFileAppender(Layout layout, String filename,
				String encoding)throws IOException {
		this.encoding = encoding;
		this.layout = layout;
		this.setFile(filename, fileAppend, true, bufferSize);
	}
	protected void setQWForFiles(Writer writer) {
		String enc;
		if((enc = getEncoding()) == null ) {
			enc = System.getProperty("file.encoding");
		}
		qw = new I18nCountingQuietWriter(writer, errorHandler, enc);
	}
	protected void subAppend(LoggingEvent event) {
		qw.write(layout.format(event));
		StringBuffer buff = new StringBuffer();
		if(layout.ignoresThrowable()) {
			String[] s = event.getThrowableStrRep();
			if (s != null) {
				int len = s.length;
				for(int i = 0; i < len; i++) {
					buff.append(s[i]);
					buff.append(Layout.LINE_SEP);
				}
			}
		}
		long filesize = ((CountingQuietWriter) qw).getCount();
		
		if((fileName != null) && (filesize >= maxFileSize)){
			rollOver();
		}
		qw.write(buff.toString());
		
		if(immediateFlush) {
			qw.flush();
		}
	}
}

import java.io.Writer;
import java.io.IOException;

import org.apache.log4j.helpers.CountingQuietWriter;
import org.apache.log4j.spi.ErrorHandler;
import org.apache.log4j.spi.ErrorCode;

public class I18nCountingQuietWriter extends CountingQuietWriter {
	
	protected String encoding;
	
	public I18nCountingQuietWriter(Writer writer, ErrorHandler eh, String encoding) {
		super(writer, eh);
		this.encoding = encoding;
	}
	public void write(String string) {
		try {
			count += string.getBytes(encoding).length;
			out.write(string);
		}
		catch(IOException e) {
			errorHandler.error("Write failure.", e, ErrorCode.WRITE_FAILURE);
		}
	}
}