public String makinStrings() {
String m = "Fred47";
String s = "Fred";
s = s + "47";
s = s.substring(0);
return s.toString();
}
这段代码创建了多少个对象?
我进行了一个简单的测试:
public static void main(String[] args) {
String m = "a";
m += "bc";
String s1 = "mabc".substring(1);
String s2 = "abc";
System.out.println(m == "abc");
System.out.println(m == s1);
System.out.println(m == s2);
System.out.println(s1 == s2);
}
如果m,s1,s2指向同一对象(“abc”),那么结果不应该是“true, true, true, true”吗?但实际结果却是“false, false, false, false”!