OnJava8-Examples/threads/SerialNumberSupplier.java

// threads/SerialNumberSupplier.java
// (c)2016 MindView LLC: see Copyright.txt
// We make no guarantees that this code is fit for any purpose.
// Visit http://mindviewinc.com/Books/OnJava/ for more book information.

public class SerialNumberSupplier {
  private static volatile int serialNumber = 0;
  public static int nextSerialNumber() {
    return serialNumber++; // Not thread-safe
  }
}