virtual method.md

package com.company;

public class Main {

    public static void main(String[] args) {
	    SoftwareEngineer a = new SoftwareEngineer();
        ((Employee)a).foo();
    }
}

package com.company;
public interface Employee
{
    default public void foo(){
        System.out.print("Employee");
    }
}

package com.company;
public class SoftwareEngineer implements Employee
{

    @Override
    public void foo()
    {
        System.out.print("SE");
    }
}

output:

SE