* might be absent" as two distinct types in your program, which can aid clarity.
 *
 * <p>Some uses of this class include
 *
 * <ul>
 *   <li>As a method return type, as an alternative to returning {@code null} to indicate that no
 *       value was available
 *   <li>To distinguish between "unknown" (for example, not present in a map) and "known to have no

  @IgnoreJRERequirement
  public static <T extends @Nullable Object> Supplier<T> memoizeWithExpiration(
      Supplier<T> delegate, Duration duration) {
    checkNotNull(delegate);
    // The alternative of `duration.compareTo(Duration.ZERO) > 0` causes J2ObjC trouble.
    checkArgument(
        !duration.isNegative() && !duration.isZero(), "duration (%s) must be > 0", duration);

   * method is overflow resilient.
   *
   * @since 14.0
   */
  public static int mean(int x, int y) {
    // Efficient method for computing the arithmetic mean.
    // The alternative (x + y) / 2 fails for large values.
    // The alternative (x + y) >>> 1 fails for negative values.
    return (x & y) + ((x ^ y) >> 1);
  }

  /**
   * Returns {@code true} if {@code n} is a <a

 * might be absent" as two distinct types in your program, which can aid clarity.
 *
 * <p>Some uses of this class include
 *
 * <ul>
 *   <li>As a method return type, as an alternative to returning {@code null} to indicate that no
 *       value was available
 *   <li>To distinguish between "unknown" (for example, not present in a map) and "known to have no

   * method is resilient to overflow.
   *
   * @since 14.0
   */
  public static long mean(long x, long y) {
    // Efficient method for computing the arithmetic mean.
    // The alternative (x + y) / 2 fails for large values.
    // The alternative (x + y) >>> 1 fails for negative values.
    return (x & y) + ((x ^ y) >> 1);
  }

  /*
   * This bitmask is used as an optimization for cheaply testing for divisibility by 2, 3, or 5.

        } catch (InvocationTargetException e) {
          assertEquals(IllegalMonitorStateException.class, e.getTargetException().getClass());
        }
      }
    };
  }

  /** Alternative to AssertionError(String, Throwable), which doesn't exist in Java 1.6 */
  private static AssertionError newAssertionError(String message, Throwable cause) {
    AssertionError e = new AssertionError(message);

 *       return Integer.toHexString(i);
 *     }
 *
 *     protected Integer doBackward(String s) {
 *       return parseUnsignedInt(s, 16);
 *     }
 *   };</pre>
 *
 * <p>An alternative using Java 8:
 *
 * <pre>{@code
 * return Converter.from(
 *     Integer::toHexString,
 *     s -> parseUnsignedInt(s, 16));
 * }</pre>
 *
 * @author Mike Ward
 * @author Kurt Alfred Kluever

        } catch (InvocationTargetException e) {
          assertEquals(IllegalMonitorStateException.class, e.getTargetException().getClass());
        }
      }
    };
  }

  /** Alternative to AssertionError(String, Throwable), which doesn't exist in Java 1.6 */
  private static AssertionError newAssertionError(String message, Throwable cause) {
    AssertionError e = new AssertionError(message);

 *       return Integer.toHexString(i);
 *     }
 *
 *     protected Integer doBackward(String s) {
 *       return parseUnsignedInt(s, 16);
 *     }
 *   };</pre>
 *
 * <p>An alternative using Java 8:
 *
 * <pre>{@code
 * return Converter.from(
 *     Integer::toHexString,
 *     s -> parseUnsignedInt(s, 16));
 * }</pre>
 *
 * @author Mike Ward
 * @author Kurt Alfred Kluever

 *         .transform(User::getId, directExecutor())
 *         .transform(ActivityService::isLoggedIn, threadPool)
 *         .catching(RpcException.class, e -> false, directExecutor());
 * }</pre>
 *
 * <h3>Alternatives</h3>
 *
 * <h4>Frameworks</h4>
 *
 * <p>When chaining together a graph of asynchronous operations, you will often find it easier to