java BufferWriter和PrintWriter效率

为什么我用BufferWriter比不用花费的时间还要多？
而用BufferOutputStream时比不用效率要高十几倍
是不是我的代码有问题
请高手给个解释

Java code:

import java.io.*;
public class BufferChar
{
public static void main(String[] args)
{
try
{
//Using BufferedWriter
long start=System.currentTimeMillis();
FileWriter fw_out=new FileWriter("file1.txt");
//BufferedWriter bfw_out=new BufferedWriter(fw_out);
PrintWriter out=new PrintWriter(new BufferedWriter(fw_out));
for(int i=0;i<10000;i++)
out.println((int)(Math.random()*10));
out.close();
long stop=System.currentTimeMillis();

//Using PrintWriter
long start1=System.currentTimeMillis();
FileWriter fw_out1=new FileWriter("file2.txt");
PrintWriter out1=new PrintWriter(fw_out1);
for(int i=0;i<10000;i++)
out1.println((int)(Math.random()*10));
out1.close();
long stop1=System.currentTimeMillis();

System.out.println("Time passed(Using BufferedWriter):"+(stop-start));
System.out.println("Time passed(Using PrintWriter):"+(stop1-start1));