Iterating through all unicode characters seems inefficient.

    static {
        final StringBuilder ws = new StringBuilder();
        final StringBuilder wsEOL = new StringBuilder();
        final StringBuilder wsRegExp = new StringBuilder();
        final StringBuilder jsonWs = new StringBuilder();

        jsonWs.append((char)0x000a);
        jsonWs.append((char)0x000d);
        JSON_WHITESPACE_EOL = jsonWs.toString();

        jsonWs.append((char)0x0009);
        jsonWs.append((char)0x0020);
        JSON_WHITESPACE = jsonWs.toString();

        for (int i = 0; i <= 0xffff; i++) {
           switch (i) {
            case 0x000a: // line feed
            case 0x000d: // carriage return (ctrl-m)
            case 0x2028: // line separator
            case 0x2029: // paragraph separator
                wsEOL.append((char)i);
            case 0x0009: // tab
            case 0x0020: // ASCII space
            case 0x000b: // tabulation line
            case 0x000c: // ff (ctrl-l)
            case 0x00a0: // Latin-1 space
            case 0x1680: // Ogham space mark
            case 0x180e: // separator, Mongolian vowel
            case 0x2000: // en quad
            case 0x2001: // em quad
            case 0x2002: // en space
            case 0x2003: // em space
            case 0x2004: // three-per-em space
            case 0x2005: // four-per-em space
            case 0x2006: // six-per-em space
            case 0x2007: // figure space
            case 0x2008: // punctuation space
            case 0x2009: // thin space
            case 0x200a: // hair space
            case 0x202f: // narrow no-break space
            case 0x205f: // medium mathematical space
            case 0x3000: // ideographic space
            case 0xfeff: // byte order mark
                ws.append((char)i);

                wsRegExp.append(Lexer.unicodeEscape((char)i));
                break;

            default:
                break;
            }
        }

        JAVASCRIPT_WHITESPACE = ws.toString();
        JAVASCRIPT_WHITESPACE_EOL = wsEOL.toString();
        JAVASCRIPT_WHITESPACE_IN_REGEXP = wsRegExp.toString();

    }