OnJava8-Examples/lowlevel/EvenProducer.java

// lowlevel/EvenProducer.java
// (c)2017 MindView LLC: see Copyright.txt
// We make no guarantees that this code is fit for any purpose.
// Visit http://OnJava8.com for more book information.
// When threads collide
// {VisuallyInspectOutput}

public class EvenProducer extends IntGenerator {
  private int currentEvenValue = 0;
  @Override
  public int next() {
    ++currentEvenValue; // [1]
    ++currentEvenValue;
    return currentEvenValue;
  }
  public static void main(String[] args) {
    EvenChecker.test(new EvenProducer());
  }
}
/* Output:
419 not even!
425 not even!
423 not even!
421 not even!
417 not even!
*/