static final class BetterStringBuffer extends AbstractStringBuilder {
  private transient String toStringCache;

  *() {
    super(16);
  }

  *(int capacity) {
    super(capacity);
  }

  *(String str) {
    super(str.length() + 16);
    append(str);
  }

  public StringBuffer(CharSequence seq) {
      this(seq.length() + 16);
      append(seq);
  }

  /**
   * Compares two {@code StringBuffer} instances lexicographically. This method
   * follows the same rules for lexicographical comparison as defined in the
   * {@linkplain java.lang.CharSequence#compare(java.lang.CharSequence,
   * java.lang.CharSequence)  CharSequence.compare(this, another)} method.
   *
   * <p>
   * For finer-grained, locale-sensitive String comparison, refer to
   * {@link java.text.Collator}.
   *
   * @implNote
   * This method synchronizes on {@code this}, the current object, but not
   * {@code StringBuffer another} with which {@code this StringBuffer} is compared.
   *
   * @param another the {@code StringBuffer} to be compared with
   *
   * @return  the value {@code 0} if this {@code StringBuffer} contains the same
   * character sequence as that of the argument {@code StringBuffer}; a negative integer
   * if this {@code StringBuffer} is lexicographically less than the
   * {@code StringBuffer} argument; or a positive integer if this {@code StringBuffer}
   * is lexicographically greater than the {@code StringBuffer} argument.
   *
   * @since 11
   */
  @Override
  public synchronized int compareTo(StringBuffer another) {
      return super.compareTo(another);
  }

  @Override
  public synchronized int length() {
      return count;
  }

  @Override
  public synchronized int capacity() {
      return super.capacity();
  }


  @Override
  public synchronized void ensureCapacity(int minimumCapacity) {
      super.ensureCapacity(minimumCapacity);
  }

  /**
   * @since      1.5
   */
  @Override
  public synchronized void trimToSize() {
      super.trimToSize();
  }

  /**
   * @throws IndexOutOfBoundsException {@inheritDoc}
   * @see        #length()
   */
  @Override
  public synchronized void setLength(int newLength) {
      toStringCache = null;
      super.setLength(newLength);
  }

  /**
   * @throws IndexOutOfBoundsException {@inheritDoc}
   * @see        #length()
   */
  @Override
  public synchronized char charAt(int index) {
      return super.charAt(index);
  }

  /**
   * @throws IndexOutOfBoundsException {@inheritDoc}
   * @since      1.5
   */
  @Override
  public synchronized int codePointAt(int index) {
      return super.codePointAt(index);
  }

  /**
   * @throws IndexOutOfBoundsException {@inheritDoc}
   * @since     1.5
   */
  @Override
  public synchronized int codePointBefore(int index) {
      return super.codePointBefore(index);
  }

  /**
   * @throws IndexOutOfBoundsException {@inheritDoc}
   * @since     1.5
   */
  @Override
  public synchronized int codePointCount(int beginIndex, int endIndex) {
      return super.codePointCount(beginIndex, endIndex);
  }

  /**
   * @throws IndexOutOfBoundsException {@inheritDoc}
   * @since     1.5
   */
  @Override
  public synchronized int offsetByCodePoints(int index, int codePointOffset) {
      return super.offsetByCodePoints(index, codePointOffset);
  }

  /**
   * @throws IndexOutOfBoundsException {@inheritDoc}
   */
  @Override
  public synchronized void getChars(int srcBegin, int srcEnd, char[] dst,
                                    int dstBegin)
  {
      super.getChars(srcBegin, srcEnd, dst, dstBegin);
  }

  /**
   * @throws IndexOutOfBoundsException {@inheritDoc}
   * @see        #length()
   */
  @Override
  public synchronized void setCharAt(int index, char ch) {
      toStringCache = null;
      super.setCharAt(index, ch);
  }

  @Override
  public synchronized StringBuffer append(Object obj) {
      toStringCache = null;
      super.append(String.valueOf(obj));
      return this;
  }

  @Override
  @HotSpotIntrinsicCandidate
  public synchronized StringBuffer append(String str) {
      toStringCache = null;
      super.append(str);
      return this;
  }

  /**
   * Appends the specified {@code StringBuffer} to this sequence.
   * <p>
   * The characters of the {@code StringBuffer} argument are appended,
   * in order, to the contents of this {@code StringBuffer}, increasing the
   * length of this {@code StringBuffer} by the length of the argument.
   * If {@code sb} is {@code null}, then the four characters
   * {@code "null"} are appended to this {@code StringBuffer}.
   * <p>
   * Let <i>n</i> be the length of the old character sequence, the one
   * contained in the {@code StringBuffer} just prior to execution of the
   * {@code append} method. Then the character at index <i>k</i> in
   * the new character sequence is equal to the character at index <i>k</i>
   * in the old character sequence, if <i>k</i> is less than <i>n</i>;
   * otherwise, it is equal to the character at index <i>k-n</i> in the
   * argument {@code sb}.
   * <p>
   * This method synchronizes on {@code this}, the destination
   * object, but does not synchronize on the source ({@code sb}).
   *
   * @param   sb   the {@code StringBuffer} to append.
   * @return  a reference to this object.
   * @since 1.4
   */
  public synchronized StringBuffer append(StringBuffer sb) {
      toStringCache = null;
      super.append(sb);
      return this;
  }

  /**
   * @since 1.8
   */
  @Override
  synchronized StringBuffer append(AbstractStringBuilder asb) {
      toStringCache = null;
      super.append(asb);
      return this;
  }

  /**
   * Appends the specified {@code CharSequence} to this
   * sequence.
   * <p>
   * The characters of the {@code CharSequence} argument are appended,
   * in order, increasing the length of this sequence by the length of the
   * argument.
   *
   * <p>The result of this method is exactly the same as if it were an
   * invocation of this.append(s, 0, s.length());
   *
   * <p>This method synchronizes on {@code this}, the destination
   * object, but does not synchronize on the source ({@code s}).
   *
   * <p>If {@code s} is {@code null}, then the four characters
   * {@code "null"} are appended.
   *
   * @param   s the {@code CharSequence} to append.
   * @return  a reference to this object.
   * @since 1.5
   */
  @Override
  public synchronized StringBuffer append(CharSequence s) {
      toStringCache = null;
      super.append(s);
      return this;
  }

  /**
   * @throws IndexOutOfBoundsException {@inheritDoc}
   * @since      1.5
   */
  @Override
  public synchronized StringBuffer append(CharSequence s, int start, int end)
  {
      toStringCache = null;
      super.append(s, start, end);
      return this;
  }

  @Override
  public synchronized StringBuffer append(char[] str) {
      toStringCache = null;
      super.append(str);
      return this;
  }

  /**
   * @throws IndexOutOfBoundsException {@inheritDoc}
   */
  @Override
  public synchronized StringBuffer append(char[] str, int offset, int len) {
      toStringCache = null;
      super.append(str, offset, len);
      return this;
  }

  @Override
  public synchronized StringBuffer append(boolean b) {
      toStringCache = null;
      super.append(b);
      return this;
  }

  @Override
  @HotSpotIntrinsicCandidate
  public synchronized StringBuffer append(char c) {
      toStringCache = null;
      super.append(c);
      return this;
  }

  @Override
  @HotSpotIntrinsicCandidate
  public synchronized StringBuffer append(int i) {
      toStringCache = null;
      super.append(i);
      return this;
  }

  public synchronized StringBuffer appendCodePoint(int codePoint) {
      toStringCache = null;
      super.appendCodePoint(codePoint);
      return this;
  }

  @Override
  public synchronized StringBuffer append(long lng) {
      toStringCache = null;
      super.append(lng);
      return this;
  }

  @Override
  public synchronized StringBuffer append(float f) {
      toStringCache = null;
      super.append(f);
      return this;
  }

  @Override
  public synchronized StringBuffer append(double d) {
      toStringCache = null;
      super.append(d);
      return this;
  }

  /**
   * @throws StringIndexOutOfBoundsException {@inheritDoc}
   * @since      1.2
   */
  @Override
  public synchronized StringBuffer delete(int start, int end) {
      toStringCache = null;
      super.delete(start, end);
      return this;
  }

  /**
   * @throws StringIndexOutOfBoundsException {@inheritDoc}
   * @since      1.2
   */
  @Override
  public synchronized StringBuffer deleteCharAt(int index) {
      toStringCache = null;
      super.deleteCharAt(index);
      return this;
  }

  /**
   * @throws StringIndexOutOfBoundsException {@inheritDoc}
   * @since      1.2
   */
  @Override
  public synchronized StringBuffer replace(int start, int end, String str) {
      toStringCache = null;
      super.replace(start, end, str);
      return this;
  }

  /**
   * @throws StringIndexOutOfBoundsException {@inheritDoc}
   * @since      1.2
   */
  @Override
  public synchronized String substring(int start) {
      return substring(start, count);
  }

  /**
   * @throws IndexOutOfBoundsException {@inheritDoc}
   * @since      1.4
   */
  @Override
  public synchronized CharSequence subSequence(int start, int end) {
      return super.substring(start, end);
  }

  /**
   * @throws StringIndexOutOfBoundsException {@inheritDoc}
   * @since      1.2
   */
  @Override
  public synchronized String substring(int start, int end) {
      return super.substring(start, end);
  }

  /**
   * @throws StringIndexOutOfBoundsException {@inheritDoc}
   * @since      1.2
   */
  @Override
  public synchronized StringBuffer insert(int index, char[] str, int offset,
                                          int len)
  {
      toStringCache = null;
      super.insert(index, str, offset, len);
      return this;
  }

  /**
   * @throws StringIndexOutOfBoundsException {@inheritDoc}
   */
  @Override
  public synchronized StringBuffer insert(int offset, Object obj) {
      toStringCache = null;
      super.insert(offset, String.valueOf(obj));
      return this;
  }

  /**
   * @throws StringIndexOutOfBoundsException {@inheritDoc}
   */
  @Override
  public synchronized StringBuffer insert(int offset, String str) {
      toStringCache = null;
      super.insert(offset, str);
      return this;
  }

  /**
   * @throws StringIndexOutOfBoundsException {@inheritDoc}
   */
  @Override
  public synchronized StringBuffer insert(int offset, char[] str) {
      toStringCache = null;
      super.insert(offset, str);
      return this;
  }

  /**
   * @throws IndexOutOfBoundsException {@inheritDoc}
   * @since      1.5
   */
  @Override
  public StringBuffer insert(int dstOffset, CharSequence s) {
      // Note, synchronization achieved via invocations of other StringBuffer methods
      // after narrowing of s to specific type
      // Ditto for toStringCache clearing
      super.insert(dstOffset, s);
      return this;
  }

  /**
   * @throws IndexOutOfBoundsException {@inheritDoc}
   * @since      1.5
   */
  @Override
  public synchronized StringBuffer insert(int dstOffset, CharSequence s,
          int start, int end)
  {
      toStringCache = null;
      super.insert(dstOffset, s, start, end);
      return this;
  }

  /**
   * @throws StringIndexOutOfBoundsException {@inheritDoc}
   */
  @Override
  public  StringBuffer insert(int offset, boolean b) {
      // Note, synchronization achieved via invocation of StringBuffer insert(int, String)
      // after conversion of b to String by super class method
      // Ditto for toStringCache clearing
      super.insert(offset, b);
      return this;
  }

  /**
   * @throws IndexOutOfBoundsException {@inheritDoc}
   */
  @Override
  public synchronized StringBuffer insert(int offset, char c) {
      toStringCache = null;
      super.insert(offset, c);
      return this;
  }

  /**
   * @throws StringIndexOutOfBoundsException {@inheritDoc}
   */
  @Override
  public StringBuffer insert(int offset, int i) {
      // Note, synchronization achieved via invocation of StringBuffer insert(int, String)
      // after conversion of i to String by super class method
      // Ditto for toStringCache clearing
      super.insert(offset, i);
      return this;
  }

  /**
   * @throws StringIndexOutOfBoundsException {@inheritDoc}
   */
  @Override
  public StringBuffer insert(int offset, long l) {
      // Note, synchronization achieved via invocation of StringBuffer insert(int, String)
      // after conversion of l to String by super class method
      // Ditto for toStringCache clearing
      super.insert(offset, l);
      return this;
  }

  /**
   * @throws StringIndexOutOfBoundsException {@inheritDoc}
   */
  @Override
  public StringBuffer insert(int offset, float f) {
      // Note, synchronization achieved via invocation of StringBuffer insert(int, String)
      // after conversion of f to String by super class method
      // Ditto for toStringCache clearing
      super.insert(offset, f);
      return this;
  }

  /**
   * @throws StringIndexOutOfBoundsException {@inheritDoc}
   */
  @Override
  public StringBuffer insert(int offset, double d) {
      // Note, synchronization achieved via invocation of StringBuffer insert(int, String)
      // after conversion of d to String by super class method
      // Ditto for toStringCache clearing
      super.insert(offset, d);
      return this;
  }

  /**
   * @since      1.4
   */
  @Override
  public int indexOf(String str) {
      // Note, synchronization achieved via invocations of other StringBuffer methods
      return super.indexOf(str);
  }

  /**
   * @since      1.4
   */
  @Override
  public synchronized int indexOf(String str, int fromIndex) {
      return super.indexOf(str, fromIndex);
  }

  /**
   * @since      1.4
   */
  @Override
  public int lastIndexOf(String str) {
      // Note, synchronization achieved via invocations of other StringBuffer methods
      return lastIndexOf(str, count);
  }

  public synchronized int lastIndexOf(String str, int fromIndex) {
      return super.lastIndexOf(str, fromIndex);
  }

  public synchronized StringBuffer reverse() {
      toStringCache = null;
      super.reverse();
      return this;
  }

  public synchronized String toString() {
      if (toStringCache == null) {
          return toStringCache =
                  isLatin1() ? StringLatin1.newString(value, 0, count)
                             : StringUTF16.newString(value, 0, count);
      }
      return new String(toStringCache);
  }

  synchronized void getBytes(byte dst[], int dstBegin, byte coder) {
      super.getBytes(dst, dstBegin, coder);
  }
}