String 的一个面试题
1 public class F { 2 public static void main(String[] args) { 3 String a = "a"; 4 String b = "b"; 5 String ab = a+b;//堆 6 String ab2 = a+"b"; //堆 7 String ab3 = "a"+"b";//常量池 8 String ab4 = "ab";//常量池 9 System.out.println(ab==ab2);//false 10 System.out.println(ab3==ab2);//false 11 System.out.println(ab==ab3);//false 12 System.out.println(ab4==ab3);//true 13 } 14 }