Java静态变量

public class InstanceCounter {



   private static int numInstances = 0;



   protected static int getCount() {

      return numInstances;

   }



   private static void addInstance() {

      numInstances++;

   }



   InstanceCounter() {

      InstanceCounter.addInstance();

   }



   public static void main(String[] arguments) {

      System.out.println("Starting with " + InstanceCounter.getCount() + " instances");



      for (int i = 0; i < 500; ++i) {

         new InstanceCounter();

      }

      System.out.println("Created " + InstanceCounter.getCount() + " instances");

   }

}