We can use Reflection to access private method of a class from

outside the class. IN Java, we use getDeclaredMethod() to get

instance of a private method. Then we mark this method accessible

and finally invoke it.

In following sample code, we are accessing private method

message() of class Foo by Reflection.

FileName: Foo.java

public class Foo {

private void message(){System.out.println("hello java"); }

}

FileName: FooMethodCall.java

import java.lang.reflect.Method;

public class FooMethodCall{

public static void main(String[] args)throws Exception{

Class c = Class.forName("Foo");

Object o= c.newInstance();

Method m =c.getDeclaredMethod("message", null);

m.setAccessible(true);

m.invoke(o, null);

}

}

https://www.tutorialspoint.com/How-to-access-the-private-methods-of-a-class-from-outside-of-the-class-in-Java