Performance test

import java.text.NumberFormat;

public class Main{

    public static void main(String[] args) {
        long startTime = 0, endTime = 0;

        Child c = new Child();
        Parent p = c;
        Inter f = c;

        final long SIZE = 1000000000L;
        NumberFormat format = NumberFormat.getInstance();

        startTime = System.nanoTime();
        System.out.print("Direct refference => ");
        for(int i=0; i<= SIZE; i++){
            c.inc(i);
        }
        endTime = System.nanoTime();
        System.out.println(format.format(endTime-startTime));

        startTime = System.nanoTime();
        System.out.print("Parent refference => ");
        for(int i=0; i<= SIZE; i++){
            p.inc(i);
        }
        endTime = System.nanoTime();
        System.out.println(format.format(endTime-startTime));

        startTime = System.nanoTime();
        System.out.print("Interface refference => ");
        for(int i=0; i<= SIZE; i++){
            f.inc(i);
        }
        endTime = System.nanoTime();
        System.out.println(format.format(endTime-startTime));


        startTime = System.nanoTime();
        System.out.print("Static refference => ");
        for(int i=0; i<= SIZE; i++){
            Child.incS(i);
        }
        endTime = System.nanoTime();
        System.out.println(format.format(endTime-startTime));
    }
}

interface Inter {
    public long inc(long l);
}

class Child extends Parent implements Inter {
    public long inc(long l){
        return l+1;
    }
    public static long incS(long l){
        return l+1;
    }
}

class Parent {
    public long inc(long l){
        return l+1;
    }
}