import java.util.ArrayList;
   import java.util.List;

   public class AssertionsWithSideEffects {
       public static int iinc(int x) {
           assert x++ == 0;
           return x;
       }

      public static boolean storeBoolean(boolean b) {
          boolean y = false;
          assert y = b == true;
          return y;
      }

      public static boolean storeInt(int n) {
          boolean y = false;
          assert y = (n == 1);
          return y;
      }

      private static List<String> list = new ArrayList<String>();

      public static void addAndRemove() {
          list.add("a");
          assert list.remove(null);
      }

      public static void addAndCheckEmptiness() {
          list.add("a");
          assert !list.isEmpty();
      }

      // A sample immutable class with an "add" operation
      private static class ImmutableList<Element> {
          Object[] elements;

          public ImmutableList() {
              elements = new Object[0];
          }

          private ImmutableList(Object[] array, Element e) {
              elements = new Object[array.length + 1];
              System.arraycopy(array, 0, elements, 0, array.length);
              elements[array.length] = e;
          }

          // Does not mutate the current object but creates a new one
          public ImmutableList<Element> add(Element e) {
              return new ImmutableList<Element>(elements, e);
          }

          public boolean isEmpty() {
              return elements.length == 0;
          }
      }

      private static ImmutableList<String> il = new ImmutableList<>();

      public static void add() {
          assert !il.add("a").isEmpty();
      }
  }