【Java每日一题】20161129

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);  
    }  
}