【Java每日一題】20161129，java20161129

【Java每日一題】20161129，java20161129

package Nov2016;  
  
public class Ques1129 {  
  
    public static void main(String[] args) {  
  
        final String str = "123";  
        str = "1234";  
        System.out.println(str);  
  
        final StringBuffer sb = new StringBuffer("123");  
        sb.append("4");  
        System.out.println(sb);  
    }  
}  

今日問題： 
請問主程序輸出結果是什麼？（點擊以下“【Java每日一題】20161129”查看20161128問題解析） 

題目原發布於公眾號、簡書：【Java每日一題】20161129，【Java每日一題】20161129