@DisplayName("Should handle StringBuilder as CharSequence")
    void testJoinWithStringBuilder() {
        StringBuilder sb1 = new StringBuilder("first");
        StringBuilder sb2 = new StringBuilder("second");
        String result = StringUtil.join(",", sb1, sb2);
        assertEquals("first,second", result);
    }

    @Test
    @DisplayName("Should handle StringBuffer as CharSequence")
    void testJoinWithStringBuffer() {

    checkNotClosed();
    target.append(c);
    return this;
  }

  @Override
  public Writer append(@Nullable CharSequence charSeq) throws IOException {
    checkNotClosed();
    target.append(charSeq);
    return this;
  }

  @Override
  public Writer append(@Nullable CharSequence charSeq, int start, int end) throws IOException {
    checkNotClosed();
    target.append(charSeq, start, end);
    return this;

    public DefaultLog(Logger logger) {
        this.logger = requireNonNull(logger);
    }

    @Override
    public void debug(CharSequence content) {
        if (isDebugEnabled()) {
            logger.debug(toString(content));
        }
    }

    @Override
    public void debug(CharSequence content, Throwable error) {
        if (isDebugEnabled()) {
            logger.debug(toString(content), error);
        }
    }

   * the {@code charSequence} is mutated while it is being read, so don't do that.
   *
   * @since 15.0 (since 14.0 as {@code CharStreams.asCharSource(String)})
   */
  public static CharSource wrap(CharSequence charSequence) {
    return charSequence instanceof String
        ? new StringCharSource((String) charSequence)
        : new CharSequenceCharSource(charSequence);
  }

  /**

      checkNotNull(sequence);
      return "";
    }

    @Override
    public String replaceFrom(CharSequence sequence, char replacement) {
      char[] array = new char[sequence.length()];
      Arrays.fill(array, replacement);
      return new String(array);
    }

    @Override
    public String replaceFrom(CharSequence sequence, CharSequence replacement) {

  static final int EXCLUSION_SHIFT = 11;
  static final int WILDCARD_SHIFT = 12;
  static final int EXACT_SHIFT = 14;

  final CharSequence trieData;
  final CharSequence stringPool;

  PublicSuffixTrie(
      ImmutableList<CharSequence> trieDataChunks,
      ImmutableList<CharSequence> stringPoolChunks,
      int chunkShift) {
    this.trieData = new ChunksCharSequence(trieDataChunks, chunkShift);

   * Iterator}, which may be lazily evaluated. If you want an eagerly computed {@link List}, use
   * {@link #splitToList(CharSequence)}.
   *
   * @param sequence the sequence of characters to split
   * @return an iteration over the segments split from the parameter
   */
  public Iterable<String> split(CharSequence sequence) {
    checkNotNull(sequence);

    return new Iterable<String>() {
      @Override

    // This benchmark has no concept of "noWorkToDo".
    String upperString = testString.toUpperCase();
    CharSequence testSeq = new StringBuilder(testString);
    CharSequence upperSeq = new StringBuilder(upperString);
    CharSequence[] lhs = new CharSequence[] {testString, testSeq, testString, testSeq};
    CharSequence[] rhs = new CharSequence[] {upperString, upperString, upperSeq, upperSeq};

    boolean dummy = false;

  abstract int maxDecodedSize(int chars);

  abstract int decodeTo(byte[] target, CharSequence chars) throws DecodingException;

  CharSequence trimTrailingPadding(CharSequence chars) {
    return checkNotNull(chars);
  }

  // Modified encoding generators

  /**

    /**
     * @see org.apache.maven.plugin.logging.Log#debug(java.lang.CharSequence)
     */
    @Override
    public void debug(CharSequence content) {
        print("debug", content);
    }

    /**
     * @see org.apache.maven.plugin.logging.Log#debug(java.lang.CharSequence, java.lang.Throwable)
     */
    @Override
    public void debug(CharSequence content, Throwable error) {
        print("debug", content, error);
    }