String是final类，常规情况下其值是不可变的。但是可以通过非常规方法——反射进行修改

/** 通过反射的方式来修改字符串String类的值
* Created by liaoqianwen on 2016/7/8.
*/

public class StringReflectTest {
public static void main(String[] args) throws NoSuchFieldException, IllegalAccessException {
String name = "angel";
String name1 = "angel";

Field strField = String.class.getDeclaredField("value");
strField.setAccessible(true);
char[] data = (char[])strField.get(name);
data[4] = 'r';
System.out.println(name);
System.out.println(name1);
System.out.println(name == name1);

}
}