/**
     * Asserts:
     * <p/>
     * <ul>
     * <li><code>string.length == null</code>
     * <li><code>string.length == 0</code>
     * </ul>
     */
    private static boolean validateStringEmpty(
            List<BuilderProblem> problems, String fieldName, String string, String message) {
        if (string == null || string.length() == 0) {
            return true;
        }

             */
            String className = repo.getLayout().getClass().getSimpleName();
            if (className.endsWith("RepositoryLayout")) {
                String layout = className.substring(0, className.length() - "RepositoryLayout".length());
                if (!layout.isEmpty()) {
                    layout = Character.toLowerCase(layout.charAt(0)) + layout.substring(1);
                    return layout;
                }
            }

    boolean containsValue(Object value) {
      try {
        if (count != 0) { // read-volatile
          AtomicReferenceArray<E> table = this.table;
          int length = table.length();
          for (int i = 0; i < length; ++i) {
            for (E e = table.get(i); e != null; e = e.getNext()) {
              V entryValue = getLiveValue(e);
              if (entryValue == null) {
                continue;

   */
  static @Nullable Object[] copyAsObjectArray(@Nullable Object[] elements, int offset, int length) {
    checkPositionIndexes(offset, offset + length, elements.length);
    if (length == 0) {
      return new Object[0];
    }
    @Nullable Object[] result = new Object[length];
    System.arraycopy(elements, offset, result, 0, length);
    return result;
  }

  @CanIgnoreReturnValue

            return a;
        }
        if (a.length == 0) {
            return b;
        }
        if (b.length == 0) {
            return a;
        }
        final boolean[] array = (boolean[]) Array.newInstance(boolean.class, a.length + b.length);
        System.arraycopy(a, 0, array, 0, a.length);
        System.arraycopy(b, 0, array, a.length, b.length);
        return array;
    }

    /**

	if err != nil {
		t.Fatal(err)
	}
	if n != length {
		t.Errorf("erasureCreateFile returned %d, expected %d", n, length)
	}

	// To generate random offset/length.
	r := rand.New(rand.NewSource(UTCNow().UnixNano()))

	buf := &bytes.Buffer{}

	// Verify erasure.Decode() for random offsets and lengths.
	for i := 0; i < iterations; i++ {
		offset := r.Int63n(length)
		readLen := r.Int63n(length - offset)

   */
  public static byte[] concat(byte[]... arrays) {
    int length = 0;
    for (byte[] array : arrays) {
      length += array.length;
    }
    byte[] result = new byte[length];
    int pos = 0;
    for (byte[] array : arrays) {
      System.arraycopy(array, 0, result, pos, array.length);
      pos += array.length;
    }
    return result;
  }

  /**

      offset = Math.min(offset, this.length);
      length = Math.min(length, this.length - offset);
      int newOffset = this.offset + (int) offset;
      return new ByteArrayByteSource(bytes, newOffset, (int) length);
    }

    @Override
    public String toString() {
      return "ByteSource.wrap("

      String[] suffix = {"f", "g"};
      String[] all = new String[elements.length + suffix.length];
      System.arraycopy(elements, 0, all, 0, elements.length);
      System.arraycopy(suffix, 0, all, elements.length, suffix.length);
      return ImmutableList.copyOf(all).subList(0, elements.length);
    }
  }

  public static class ImmutableListTailSubListGenerator extends TestStringListGenerator {

    @Override
    public Entry<K, V>[] createArray(int length) {
      return generator.createArray(length);
    }

    @Override
    public Iterable<Entry<K, V>> order(List<Entry<K, V>> insertionOrder) {
      return generator.order(insertionOrder);
    }

    @SuppressWarnings("unchecked")
    @Override
    public K[] createKeyArray(int length) {
      return (K[]) new Object[length];
    }

    @SuppressWarnings("unchecked")