*
         * Ideally we'd have a real eviction policy, but until we see a problem in practice, I hope
         * that this will suffice. I have not even benchmarked with different size limits.
         */
        if (validClasses.size() > 1000) {
          validClasses.clear();
        }

        validClasses.add(new WeakReference<Class<? extends Exception>>(exceptionClass));
      }
    }

  }

  /**
   * Calls get() repeatedly from many different threads, and tests that all of the removed entries
   * (removed because of size limits or expiration) trigger appropriate removal notifications.
   */
  @GwtIncompatible // QueuingRemovalListener

  public void testRemovalNotification_get_basher() throws InterruptedException {
    int nTasks = 1000;

    this.replacements = escaperMap.getReplacementArray();
    this.replacementsLength = replacements.length;
    if (safeMax < safeMin) {
      // If the safe range is empty, set the range limits to opposite extremes
      // to ensure the first test of either value will fail.
      safeMax = -1;
      safeMin = Integer.MAX_VALUE;
    }
    this.safeMin = safeMin;
    this.safeMax = safeMax;

  }

  /**
   * Calls get() repeatedly from many different threads, and tests that all of the removed entries
   * (removed because of size limits or expiration) trigger appropriate removal notifications.
   */
  @GwtIncompatible // QueuingRemovalListener

  public void testRemovalNotification_get_basher() throws InterruptedException {
    int nTasks = 1000;

    }
  }

  public void testLimit() {
    Iterable<String> iterable = Lists.newArrayList("foo", "bar", "baz");
    FluentIterable<String> limited = FluentIterable.from(iterable).limit(2);

    assertEquals(ImmutableList.of("foo", "bar"), Lists.newArrayList(limited));
    assertCanIterateAgain(limited);
    assertEquals("[foo, bar]", limited.toString());
  }

  public void testLimit_illegalArgument() {
    try {

@ElementTypesAreNonnullByDefault
final class Java8Compatibility {
  static void clear(Buffer b) {
    b.clear();
  }

  static void flip(Buffer b) {
    b.flip();
  }

  static void limit(Buffer b, int limit) {
    b.limit(limit);
  }

  static void position(Buffer b, int position) {
    b.position(position);
  }

  private Java8Compatibility() {}

  /**
   * Puts the remaining bytes of a byte buffer into this sink. {@code bytes.position()} is the first
   * byte written, {@code bytes.limit() - 1} is the last. The position of the buffer will be equal
   * to the limit when this method returns.
   *
   * @param bytes a byte buffer
   * @return this instance
   * @since 23.0
   */
  @CanIgnoreReturnValue

        int limit = pos + random.nextInt(value.length - pos + 1);
        for (PrimitiveSink sink : sinks) {
          ByteBuffer buffer = ByteBuffer.wrap(value);
          Java8Compatibility.position(buffer, pos);
          Java8Compatibility.limit(buffer, limit);
          sink.putBytes(buffer);
          assertEquals(limit, buffer.limit());
          assertEquals(limit, buffer.position());
        }
      }

   */
  static BigInteger randomNonNegativeBigInteger(int numBits) {
    int digits = RANDOM_SOURCE.nextInt(numBits);
    if (digits == 0) {
      return new BigInteger(1, RANDOM_SOURCE);
    } else {
      return new BigInteger(digits, RANDOM_SOURCE).setBit(digits);
    }
  }

  /**
   * Equivalent to calling randomPositiveBigInteger(numBits) and then flipping the sign with 50%

   * null} if no replacement should be made. This method is intended for use in tests through the
   * {@code EscaperAsserts} class; production users of {@link CharEscaper} should limit themselves
   * to its public interface.
   *
   * @param c the character to escape if necessary
   * @return the replacement string, or {@code null} if no escaping was needed
   */
  @CheckForNull