checkNotNull(appendable, "appendable");
        checkNotNull(parts, "parts");
        while (parts.hasNext()) {
          Object part = parts.next();
          if (part != null) {
            appendable.append(Joiner.this.toString(part));
            break;
          }
        }
        while (parts.hasNext()) {
          Object part = parts.next();

 * factories for I/O streams that provide many convenience methods that handle both opening and
 * closing streams for you.
 *
 * <p>This package is a part of the open-source <a href="https://github.com/google/guava">Guava</a>
 * library. For more information on Sources and Sinks as well as other features of this package, see

 * or implied. See the License for the specific language governing permissions and limitations under
 * the License.
 */

/**
 * Basic utility libraries and interfaces.
 *
 * <p>This package is a part of the open-source <a href="https://github.com/google/guava">Guava</a>
 * library.
 *
 * <h2>Contents</h2>
 *
 * The classes in this package that are most commonly useful are:
 *
 * <h3>String utilities</h3>
 *

 * the License.
 */

/**
 * Static utilities for the eight primitive types and {@code void}, and value types for treating
 * them as unsigned or storing them in immutable arrays.
 *
 * <p>This package is a part of the open-source <a href="https://github.com/google/guava">Guava</a>
 * library.
 *
 * <p>See the Guava User Guide article on <a
 * href="https://github.com/google/guava/wiki/PrimitivesExplained">primitive utilities</a>.
 *

  public static final Charset UTF_16 = Charset.forName("UTF-16");

  /*
   * Please do not add new Charset references to this class, unless those character encodings are
   * part of the set required to be supported by all Java platform implementations! Any Charsets
   * initialized here may cause unexpected delays when this class is loaded. See the Charset

        checkNotNull(appendable, "appendable");
        checkNotNull(parts, "parts");
        while (parts.hasNext()) {
          Object part = parts.next();
          if (part != null) {
            appendable.append(Joiner.this.toString(part));
            break;
          }
        }
        while (parts.hasNext()) {
          Object part = parts.next();

   */
  private static boolean validateSyntax(List<String> parts) {
    int lastIndex = parts.size() - 1;

    // Validate the last part specially, as it has different syntax rules.

    if (!validatePart(parts.get(lastIndex), true)) {
      return false;
    }

    for (int i = 0; i < lastIndex; i++) {
      String part = parts.get(i);
      if (!validatePart(part, false)) {
        return false;
      }
    }

/**
 * Thread that finalizes referents. All references should implement {@code
 * com.google.common.base.FinalizableReference}.
 *
 * <p>While this class is public, we consider it to be *internal* and not part of our published API.
 * It is public so we can access it reflectively across class loaders in secure environments.
 *
 * <p>This class can't depend on other Guava code. If we were to load this class in the same class

      return specialCases.get(constantName);
    }
    List<String> parts = Lists.newArrayList();
    for (String part : SPLITTER.split(constantName)) {
      if (!uppercaseAcronyms.contains(part)) {
        part = part.charAt(0) + Ascii.toLowerCase(part.substring(1));
      }
      parts.add(part);
    }
    return JOINER.join(parts);
  }

      return specialCases.get(constantName);
    }
    List<String> parts = Lists.newArrayList();
    for (String part : SPLITTER.split(constantName)) {
      if (!uppercaseAcronyms.contains(part)) {
        part = part.charAt(0) + Ascii.toLowerCase(part.substring(1));
      }
      parts.add(part);
    }
    return JOINER.join(parts);
  }