Question

I have a parent, and a child class,

class Parent
{
    // variables
    // constructor
}

class Child extends Parent
{
    // variables
    // constructor
    public void AChildMethod()
    {
        // do something
    }
}

And inside my program, I have a reference of the main type, but it references to a child type

Parent obj = new Child();

Is it possible to call the “AChildMethod” method of the child in a way like this?

obj.AChildMethod();

Thank you very much in advance.

Answer 1

You can check whether it really is an instance of the Child class, and then simply cast to the child type:

if ( obj instanceof Child ) {
    ((Child) obj).aChildMethod();
    // or
    Child childObj = (Child) obj;
    childObj.aChildMethod();
}

However, if a cast like this is needed, it could be an indication that your class hierarchy should be improved.