New JITWatch sandbox example for reducing a megamorphic callsite

public class MegamorphicBypass
{
 public interface Coin { void deposit(); }

 public class Nickel implements Coin { public void deposit() { moneyBox += 5; } }

 public class Dime implements Coin { public void deposit() { moneyBox += 10; } }

 public class Quarter implements Coin { public void deposit() { moneyBox += 25; } }

 public static int moneyBox = 0;

 public MegamorphicBypass()
 {
   Coin nickel = new Nickel();
   Coin dime = new Dime();
   Coin quarter = new Quarter();

   Coin coin = null;

   final int maxImplementations = 3;

   for (int i = 0; i < 1_000_000; i++)
   {
      switch(i % maxImplementations)
      {
        case 0: coin = nickel; break;
        case 1: coin = dime; break;
        case 2: coin = quarter; break;
      }

      // peel off one type with an instanceof check
      if (coin instanceof Nickel)
      {
        coin.deposit();
      }
      else
      {
        // this callsite will now only observe 2 types and can use bimorphic inlining
        coin.deposit();
      }
   }

   System.out.println("moneyBox:" + moneyBox);
 }

 public static void main(String[] args) {
   new MegamorphicBypass();
 }
}