Magical Java Puzzle: “Pat The Unicorns”

gistfile1.java

import java.io.PrintStream;

public class MagicalLand {
  public static void main(String[] args) {
    for (int i = 0; i < (Math.random() * 500) + 2; i++) {
      if (Unicorn.pat()) {
        System.out.println("UNICORN #1: PAT THIS UNICORN ONCE");
      }
    }
 
    for (int i = 0; i < (Math.random() * 500) + 2; i++) {
      if (Unicorn.pat()) {
        System.out.println("UNICORN #2: PAT THIS UNICORN ONCE");
      }
    }
    System.out.println("END OF PROGRAM");
  }
}

class Unicorn {
    static String lastOutput = null;

    static {
        System.setOut(new PrintStream(System.out) {
            @Override
            public void println(String x) {
                switch (x) {
                    case "UNICORN #1: PAT THIS UNICORN ONCE":
                        if (lastOutput == null) {
                            super.println(x);
                        }
                        break;
                    case "UNICORN #2: PAT THIS UNICORN ONCE":
                        if (!lastOutput.equals(x)) {
                            super.println(x);
                        }
                        break;
                    default:
                        super.println(x);
                }
                lastOutput = x;
            }
        });
    }

    static boolean pat() {
        return true;
    }
}