JavaSE8基础 StringBuffer与String变量在追加字符串后，引用变量的地址发生改变

os ：windows7 x64
    jdk：jdk-8u131-windows-x64
    ide：Eclipse Oxygen Release (4.7.0)
    
    
code：

package jizuiku0;

public class Demo11 {
	public static void main(String[] args) {
		String str1 = "cnblog";
		String str2 = str1 + "jizuiku";
		System.out.println(str1 == str2);

		StringBuffer sb1 = new StringBuffer("cnblog");//创建了缓冲区A,A里面存着 cnblog
		StringBuffer sb2 = sb1.append("jizuiku");//往缓冲区A里面追加 append,缓冲区A还是缓冲区A
		System.out.println(sb1 == sb2);//sb1、sb2都指向的是缓冲区A
	}
}

result：

XjadCode(为了弄清这其中发生了什么，用反编译查看)：

// Decompiled by Jad v1.5.8e2. Copyright 2001 Pavel Kouznetsov.
// Jad home page: http://kpdus.tripod.com/jad.html
// Decompiler options: packimports(3) fieldsfirst ansi space
// Source File Name:   Demo11.java

package jizuiku0;

import java.io.PrintStream;

public class Demo11
{

	public Demo11()
	{
	}

	public static void main(String args[])
	{
		String str1 = "cnblog";
		String str2 = (new StringBuilder(String.valueOf(str1))).append("jizuiku").toString();
		System.out.println(str1 == str2);
		StringBuffer sb1 = new StringBuffer("cnblog");
		StringBuffer sb2 = sb1.append("jizuiku");
		System.out.println(sb1 == sb2);
	}
}

　　看了反编译后的代码，(⊙o⊙)哦，原来是这样编译的，懂了！