gistfile1.java

import java.io.PrintStream;
import java.util.HashSet;
import java.util.Set;

/**
 * @author Lorber Sebastien <i>(lorber.sebastien@gmail.com)</i>
 */
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 {
    PrintStream printOnlyOneStream = new PrintStream(System.out) {
      private Set<String> alreadyWritten = new HashSet<String>();
      @Override
      public void println(String string) {
        if ( !alreadyWritten.contains(string) ) {
          print(string+"\n");
          alreadyWritten.add(string);
        }
      }
    };
    System.setOut(printOnlyOneStream);
  }

  public static boolean pat() {
    return true;
  }