/**
 * Static convenience methods that help a method or constructor check whether it was invoked
 * correctly (that is, whether its <i>preconditions</i> were met).
 *
 * <p>If the precondition is not met, the {@code Preconditions} method throws an unchecked exception
 * of a specified type, which helps the method in which the exception was thrown communicate that
 * its caller has made a mistake. This allows constructs such as
 *

    try {
      Iterators.getOnlyElement(iterator);
      fail();
    } catch (IllegalArgumentException expected) {
      assertThat(expected).hasMessageThat().isEqualTo("expected one element but was: <one, two>");
    }
  }

  public void testGetOnlyElement_noDefault_fiveElements() {
    Iterator<String> iterator = asList("one", "two", "three", "four", "five").iterator();
    try {

        assertThrows(ExecutionException.class, () -> cacheChecked.getAll(asList(new Object())));
    assertThat(caughtEe).hasCauseThat().isSameInstanceAs(ee);
  }

  @AndroidIncompatible // Bug? expected:<1> but was:<2>
  public void testConcurrentLoading() throws InterruptedException {
    testConcurrentLoading(CacheBuilder.newBuilder());
  }

  private static void testConcurrentLoading(CacheBuilder<Object, Object> builder)

      }
    }

    /**
     * Throws UnsupportedOperationException. A future version may support this operation. Then the
     * value for any given key will be the one that was last supplied in a {@code put} operation for
     * that key.
     *
     * @throws UnsupportedOperationException always
     * @since 31.1
     * @deprecated This method is not currently implemented, and may never be.

   *   <li>{@link Cancellation} terminal state, {@code cancel} was called.
   *   <li>{@link Failure} terminal state, {@code setException} was called.
   *   <li>{@link SetFuture} intermediate state, {@code setFuture} was called.
   *   <li>{@link #NULL} terminal state, {@code set(null)} was called.
   *   <li>Any other non-null value, terminal state, {@code set} was called with a non-null
   *       argument.
   * </ul>
   */

        assertThrows(ExecutionException.class, () -> cacheChecked.getAll(asList(new Object())));
    assertThat(caughtEe).hasCauseThat().isSameInstanceAs(ee);
  }

  @AndroidIncompatible // Bug? expected:<1> but was:<2>
  public void testConcurrentLoading() throws InterruptedException {
    testConcurrentLoading(CacheBuilder.newBuilder());
  }

  private static void testConcurrentLoading(CacheBuilder<Object, Object> builder)

      }
    }

    /**
     * Throws UnsupportedOperationException. A future version may support this operation. Then the
     * value for any given key will be the one that was last supplied in a {@code put} operation for
     * that key.
     *
     * @throws UnsupportedOperationException always
     * @since 31.1
     * @deprecated This method is not currently implemented, and may never be.

    step4Waiter.awaitStarted();

    // Step 1 is not cancelled because it was done.
    assertWithMessage("step1.statusFuture().isCancelled()")
        .that(step1.statusFuture().isCancelled())
        .isFalse();
    // But its closeable is closed.
    assertClosed(closeable1);

    // Step 2 is cancelled because it wasn't complete.
    assertWithMessage("step2.statusFuture().isCancelled()")

    /**
     * Returns the current value being referenced, or {@code null} if there is none (e.g. because
     * either it got collected, or {@link #clear} was called, or it wasn't set in the first place).
     */
    @CheckForNull
    V get();

    /** Returns the entry which contains this {@link WeakValueReference}. */
    E getEntry();

    step4Waiter.awaitStarted();

    // Step 1 is not cancelled because it was done.
    assertWithMessage("step1.statusFuture().isCancelled()")
        .that(step1.statusFuture().isCancelled())
        .isFalse();
    // But its closeable is closed.
    assertClosed(closeable1);

    // Step 2 is cancelled because it wasn't complete.
    assertWithMessage("step2.statusFuture().isCancelled()")