java原生序列化慢在哪里？

package com.clq.netty.serializable;

import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.ObjectOutputStream;
import java.io.Serializable;
import java.nio.ByteBuffer;

/**
 * Created by clq on 2018/7/20.
 */
public class UserInfo implements Serializable{

    private String name;
    private int id;

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public byte[] CodeC(ByteBuffer byteBuffer) {
        byteBuffer.clear();
       // ByteBuffer byteBuffer = ByteBuffer.allocate(1024);
        byte[] bytes = this.getName().getBytes();
        byteBuffer.putInt(bytes.length);
        byteBuffer.put(bytes);
        byteBuffer.putInt(this.getId());
        byteBuffer.flip();
        bytes = null;
        byte [] bytes1 = new byte[byteBuffer.remaining()];
        byteBuffer.get(bytes1);
        return bytes1;
    }

    public static void main(String[] args) throws IOException {
        UserInfo userInfo = new UserInfo();
        userInfo.setId(1234);
        userInfo.setName("Welcome to Serializable");
        long begin = System.currentTimeMillis();
        for(int i=0; i<1000000; i++) {
            ByteArrayOutputStream bos = new ByteArrayOutputStream();
            ObjectOutputStream oos = new ObjectOutputStream(bos);
            oos.writeObject(userInfo);
            oos.flush();
            oos.close();
            byte[] bytes = bos.toByteArray();
            bos.close();
        }
        System.out.println("Java序列化耗时： "+(System.currentTimeMillis()-begin)+"ms");
        ByteBuffer byteBuffer = ByteBuffer.allocate(1024);
        Long start =System.currentTimeMillis();
        for(int i=0;i<1000000;i++) {
            byte[] bytes = userInfo.CodeC(byteBuffer);
        }
        System.out.println("二进制序列化："+(System.currentTimeMillis()-start)+"ms");
        // System.out.println("JDK Serializable length:"+bytes.length);
       // System.out.println("NIO Serializable length:"+userInfo.CodeC().length);
    }
}

public static void main(String[] args) throws IOException {
        UserInfo userInfo = new UserInfo();
        userInfo.setId(1234);
        userInfo.setName("Welcome to Serializable");
        ByteArrayOutputStream bos = new ByteArrayOutputStream();
        ObjectOutputStream oos = new ObjectOutputStream(bos);
        oos.writeObject(userInfo);
        oos.flush();
        oos.close();
        byte[] bytes = bos.toByteArray();
        bos.close();
        System.out.println("JDK Serializable length:"+bytes.length);
        ByteBuffer buffer = ByteBuffer.allocate(1024);
        System.out.println("NIO Serializable length:"+userInfo.CodeC(buffer).length);
    }

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0000 0017 5765 6c63 6f6d 6520 746f 2053   
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