import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * 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

    ImmutableSet<Integer> elements = ImmutableSet.of(1, 2, 3);
    Set<Set<Integer>> powerSet = powerSet(elements);
    // The API doesn't promise this iteration order, but it's convenient here.
    Iterator<Set<Integer>> i = powerSet.iterator();
    assertEquals(ImmutableSet.of(), i.next());
    assertEquals(ImmutableSet.of(1), i.next());
    assertEquals(ImmutableSet.of(2), i.next());

        } while (oldHead != Waiter.TOMBSTONE);
      }
      // re-read value, if we get here then we must have observed a TOMBSTONE while trying to add a
      // waiter.
      // requireNonNull is safe because value is always set before TOMBSTONE.
      return getDoneValue(requireNonNull(value));
    }
    // If we get here then we have remainingNanos < SPIN_THRESHOLD_NANOS and there is no node on the
    // waiters list

 * package will refer to the class. Plus, @ParametricNullness is only a temporary workaround,
 * anyway, so we just need to get by without the annotations here until Kotlin better understands
 * our other nullness annotations.
 */
final class Synchronized {
  private Synchronized() {}

  static class SynchronizedObject implements Serializable {
    final Object delegate;

    assertEquals("", result.get("test"));
    assertEquals("2", result.get("second"));
    assertEquals("item :   a short  phrase   ", result.get("Third"));
    assertFalse(result.containsKey("not here"));

    // Test loading system properties
    result = Maps.fromProperties(System.getProperties());
    assertTrue(result.containsKey("java.version"));

    // Test that defaults work, too.

    assertEquals("", result.get("test"));
    assertEquals("2", result.get("second"));
    assertEquals("item :   a short  phrase   ", result.get("Third"));
    assertFalse(result.containsKey("not here"));

    // Test loading system properties
    result = Maps.fromProperties(System.getProperties());
    assertTrue(result.containsKey("java.version"));

    // Test that defaults work, too.

    TypeToken<List<String>> b = new TypeToken<List<String>>() {};
    assertEquals(a, b);
  }

  public <T> void testVariableTypeTokenNotAllowed() {
    /*
     * We'd use assertThrows here, but that causes no exception to be thrown under Java 8,
     * presumably because the ThrowingRunnable lambda triggers some kind of bug in Java 8's
     * reflection implementation.
     */
    try {

  }

  /**
   * Determines whether a character is whitespace according to the latest Unicode standard, as
   * illustrated <a
   * href="http://unicode.org/cldr/utility/list-unicodeset.jsp?a=%5Cp%7Bwhitespace%7D">here</a>.
   * This is not the same definition used by other Java APIs. (See a <a
   * href="https://goo.gl/Y6SLWx">comparison of several definitions of "whitespace"</a>.)
   *

   * higher than performing just the operation without enforcing the capacity constraint.
   *
   * This implementation uses a per-segment queue to record a memento of the additions, removals,
   * and accesses that were performed on the map. The queue is drained on writes and when it exceeds
   * its capacity threshold.
   *
   * The Least Recently Used page replacement algorithm was chosen due to its simplicity, high hit

     * exceptions' docs suggest that either is acceptable. Google's Java Practices page recommends
     * IllegalArgumentException here, in part to keep its recommendation simple: Static methods
     * should throw IllegalStateException only when they use static state.
     *
     * Why do we deviate here? The answer: We want for fluentFuture.getDone() to throw the same
     * exception as Futures.getDone(fluentFuture).
     */