driver-legacy/src/main/com/mongodb/util/JSON.java
public String parseString(final boolean needQuote) {
        char quot = 0;
        if (check('\'')) {
            quot = '\'';
        } else if (check('\"')) {
            quot = '\"';
        } else if (needQuote) {
            throw new JSONParseException(s, pos);
        }

        char current;

        if (quot > 0) {
            read(quot);
        }
        StringBuilder buf = new StringBuilder();
        int start = pos;
        while (pos < s.length()) {
            current = s.charAt(pos);
            if (quot > 0) {
                if (current == quot) {
                    break;
                }
            } else {
                if (current == ':' || current == ' ') {
                    break;
                }
            }

            if (current == '\\') {
                pos++;

                char x = get();

                char special = 0;

                //CHECKSTYLE:OFF
                switch (x) {
                    case 'u':  // decode unicode
                        buf.append(s.substring(start, pos - 1));
                        pos++;
                        int tempPos = pos;

                        readHex();
                        readHex();
                        readHex();
                        readHex();

                        int codePoint = Integer.parseInt(s.substring(tempPos, tempPos + 4), 16);
                        buf.append((char) codePoint);

                        start = pos;
                        continue;
                    case 'n':
                        special = '\n';
                        break;
                    case 'r':
                        special = '\r';
                        break;
                    case 't':
                        special = '\t';
                        break;
                    case 'b':
                        special = '\b';
                        break;
                    case '"':
                        special = '\"';
                        break;
                    case '\\':
                        special = '\\';
                        break;
                    default:
                        break;
                }
                //CHECKSTYLE:ON

                buf.append(s.substring(start, pos - 1));
                if (special != 0) {
                    pos++;
                    buf.append(special);
                }
                start = pos;
                continue;
            }
            pos++;
        }
        buf.append(s.substring(start, pos));
        if (quot > 0) {
            read(quot);
        }
        return buf.toString();
    }
public String parseString(final boolean needQuote) {
        char quot = 0;
        if (check('\'')) {
            quot = '\'';
        } else if (check('\"')) {
            quot = '\"';
        } else if (needQuote) {
            throw new JSONParseException(s, pos);
        }

        char current;

        if (quot > 0) {
            read(quot);
        }
        StringBuilder buf = new StringBuilder();
        int start = pos;
        while (pos < s.length()) {
            current = s.charAt(pos);
            if (quot > 0) {
                if (current == quot) {
                    break;
                }
            } else {
                if (current == ':' || current == ' ') {
                    break;
                }
            }

            if (current == '\\') {
                pos++;

                char x = get();

                char special = 0;

                //CHECKSTYLE:OFF
                switch (x) {
                    case 'u':  // decode unicode
                        buf.append(s.substring(start, pos - 1));
                        pos++;
                        int tempPos = pos;

                        readHex();
                        readHex();
                        readHex();
                        readHex();

                        int codePoint = Integer.parseInt(s.substring(tempPos, tempPos + 4), 16);
                        buf.append((char) codePoint);

                        start = pos;
                        continue;
                    case 'n':
                        special = '\n';
                        break;
                    case 'r':
                        special = '\r';
                        break;
                    case 't':
                        special = '\t';
                        break;
                    case 'b':
                        special = '\b';
                        break;
                    case '"':
                        special = '\"';
                        break;
                    case '\\':
                        special = '\\';
                        break;
                    default:
                        break;
                }
                //CHECKSTYLE:ON

                buf.append(s.substring(start, pos - 1));
                if (special != 0) {
                    pos++;
                    buf.append(special);
                }
                start = pos;
                continue;
            }
            pos++;
        }
        buf.append(s.substring(start, pos));
        if (quot > 0) {
            read(quot);
        }
        return buf.toString();
    }
Parses a string.

@return the next string.
@throws JSONParseException if invalid JSON is found