请教BufferedOutputStream的write方法

import java.io.*;
import java.net.*;

public class Demo {
public static void main(String[] args) throws IOException {

BufferedInputStream bis = new BufferedInputStream(new FileInputStream(
"C:\\Arrays.jpg"));
BufferedOutputStream bos = new BufferedOutputStream(
new FileOutputStream("C:\\Arrays2.jpg"));

byte[] buf1 = new byte[1000];
byte[] buf2 = new byte[1000];
int len = 0;

while ((len = bis.read(buf1)) != -1) {
System.out.println(len);
bos.write(buf2, 0, len);
}

}
}