Can we call private methods of abstract class using reflection?

Question

我们可以使用反射调用抽象类的私有方法吗？

Answer 1

Yes you can. You can use reflection . What you need -

1. The class object of Abstract Class.
2. dynamically set the method's accessibility to true . Check the code below.

class ExitPuzzle extends MyAbstractClass {
    public static void main(String... args) throws IllegalArgumentException,
            IllegalAccessException, InvocationTargetException {
        Class clazz = MyAbstractClass.class;
        Method[] methods = clazz.getDeclaredMethods();
        System.out.println(Arrays.toString(methods));
        methods[0].setAccessible(true);
        methods[0].invoke(new ExitPuzzle(), null);
    }

}

abstract class MyAbstractClass {
    private void myMethod() {
        System.out.println("in MyAbstractClass");
    }
}

O/P :

[private void MyAbstractClass.myMethod()]
in MyAbstractClass

Answer 2

您应该创建一个扩展抽象类的concrete class的实例，或者您应该为抽象类创建一个anonymous inner class instance （并覆盖标记为abstract的方法）。然后您可以使用该实例并通过setAccessible(true)使该方法可访问setAccessible(true) 。除非你搞砸了SecurityManager （在大多数情况下你不会这样做），否则这会有效。然后你可以调用方法

Answer 3

yes you can.

but you will need an object that is an instance of the abstract class for this.