public class ParentClass
{
    // I want to invoke fields and methods of the DerivedClass.
    public void method1()
    {
        DerivedClass object = new DerivedClass();
        object.int1;
        object.method2();
    }
}

class DerivedClass extends ParentClass
{
    public static final int int1 = 10;
    public void method2()
    {
        System.out.println("Hello, I am a method in the DerivedClass");
    }
}