Biased coin toss converted to unbiased coin toss.

BaisedCoin.java

import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.Random;

/**
 *
 * @author deepak
 */
public class BiasedCoin {

    public final static int HEAD = 1;
    public final static int TAIL = 0;

    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) {
        List<Integer> l = new ArrayList();

        for (int i = 0; i < 1000000; i++) {
            l.add(getTossResult());
        }

        System.out.println("Heads baised: " + Collections.frequency(l, HEAD));

        l.clear();
        for (int i = 0; i < 1000000; i++) {
            l.add(getUnbaisedTossResult());
        }

        System.out.println("Heads unbaised: " + Collections.frequency(l, HEAD));
    }

    //Biased toss
    public static int getTossResult() {
        Random r = new Random();

        //60-40 chance
        if (r.nextInt(100) > 59) {
            return HEAD;
        } else {
            return TAIL;
        }
    }

    //Unbiased toss
    public static int getUnbaisedTossResult() {
        int x, y;
        do {
            x = getTossResult();
            y = getTossResult();
        } while (x == y);
        //Break loop when not same 50-50 chance
        return x;
    }

}