如何实施"公共/受保护/私有"方法,以及如何模拟它？

public class MyClass {
    public void publicMethod() {
        System.out.println("This is a public method.");
    }

    protected void protectedMethod() {
        System.out.println("This is a protected method.");
    }

    private void privateMethod() {
        System.out.println("This is a private method.");
    }
}

public class MyClassTest {
    @Test
    public void testPublicMethod() {
        MyClass myClass = new MyClass();
        myClass.publicMethod();
    }

    @Test
    public void testProtectedMethod() throws NoSuchMethodException, IllegalAccessException, InvocationTargetException {
        MyClass myClass = new MyClass();
        Method protectedMethod = MyClass.class.getDeclaredMethod("protectedMethod");
        protectedMethod.setAccessible(true);
        protectedMethod.invoke(myClass);
    }

    @Test
    public void testPrivateMethod() throws NoSuchMethodException, IllegalAccessException, InvocationTargetException {
        MyClass myClass = new MyClass();
        Method privateMethod = MyClass.class.getDeclaredMethod("privateMethod");
        privateMethod.setAccessible(true);
        privateMethod.invoke(myClass);
    }
}