public void test_append_nullValue() {
        StringBuilder buf = new StringBuilder();
        Supplier<Object> supplier = () -> null;

        monitorTarget.append(buf, "testKey", supplier);
        assertEquals("\"testKey\":null", buf.toString());
    }

    // Test append method with Integer value
    public void test_append_integerValue() {
        StringBuilder buf = new StringBuilder();

                break;
            case "appendJvmStats":
                hasAppendJvmStats = true;
                assertEquals("appendJvmStats should take StringBuilder parameter", 1, method.getParameterCount());
                assertEquals("appendJvmStats should take StringBuilder", StringBuilder.class, method.getParameterTypes()[0]);

    Object[] array = newArrayList(set).toArray(new Integer[0]);
    assertEquals("", joiner.join(array));

    StringBuilder sb1FromIterable = new StringBuilder();
    assertSame(sb1FromIterable, joiner.appendTo(sb1FromIterable, set));
    assertEquals(0, sb1FromIterable.length());

    StringBuilder sb1FromIterator = new StringBuilder();
    assertSame(sb1FromIterator, joiner.appendTo(sb1FromIterator, set));

     */
    public static String encodeAttrQuot(final String s) {
        if (s == null) {
            return null;
        }
        final char[] content = s.toCharArray();
        final StringBuilder buf = new StringBuilder(s.length() + 100);
        for (final char element : content) {
            switch (element) {
            case '<':
                buf.append("&lt;");
                break;
            case '>':

     * @param key the key name
     * @param supplier the value supplier
     * @return the updated buffer
     */
    protected StringBuilder append(final StringBuilder buf, final String key, final Supplier<Object> supplier) {
        final StringBuilder tempBuf = new StringBuilder();
        tempBuf.append('"').append(key).append("\":");
        try {
            final Object value = supplier.get();
            if (value == null) {

            final String v = s.substring(CONTAINS.length());
            final StringBuilder buf = new StringBuilder(100);
            return ".*" + appendFileterPath(buf, escape(v)) + ".*";
        }
        if (s.startsWith(REGEXP_IGNORE_CASE)) {
            final String v = s.substring(REGEXP_IGNORE_CASE.length());
            final StringBuilder buf = new StringBuilder(100);
            buf.append("(?i)");

   * Does not close the {@code Readable}.
   *
   * @param r the object to read from
   * @return a {@link StringBuilder} containing all the characters
   * @throws IOException if an I/O error occurs
   */
  private static StringBuilder toStringBuilder(Readable r) throws IOException {
    StringBuilder sb = new StringBuilder();
    if (r instanceof Reader) {

        map.put("ッ", new String[] { "tu", "tsu" });

        return map;
    }

    private List<StringBuilder> deepCopyBufList(final List<StringBuilder> bufList) {
        final List<StringBuilder> list = new ArrayList<>();
        bufList.forEach(buf -> list.add(new StringBuilder(buf.toString())));
        return list;
    }

    // from InputStream to StringBuilder
    //
    /**
     * Copies from an input stream to a {@link StringBuilder} using the platform default encoding.
     * <p>
     * The input stream is not closed.
     * </p>
     *
     * @param in the input stream (must not be {@literal null})
     * @param out the {@link StringBuilder} (must not be {@literal null})

    int spaceInAscii = 32;
    int sevenBitAsciiMax = 128;
    StringBuilder sb = new StringBuilder(sevenBitAsciiMax - spaceInAscii);
    for (int ch = spaceInAscii; ch < sevenBitAsciiMax; ch++) {
      sb.append((char) ch);
    }
    ASCII_CHARACTERS = sb.toString();
  }

  private static final String ALL_DIGITS;

  static {
    StringBuilder sb = new StringBuilder();
    String zeros =