// 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 } }