Java Utililty Methods String Unescape

if (-1 == s.indexOf('\\')) {
    return s;
final int length = s.length();
StringBuilder buf = new StringBuilder(length);
for (int i = 0; i < length; i++) {
    char c = s.charAt(i);
    if ('\\' != c) {
...

return s.replace("\\\"", "\"");

if (s.indexOf('\\') < 0)
    return s;
StringBuilder sb = new StringBuilder();
for (int i = 0; i < s.length(); i++) {
    char c = s.charAt(i);
    if (c == '\\' && i != (s.length() - 1)) {
        char c2 = s.charAt(i + 1);
        switch (c2) {
...

StringBuffer sbuf = new StringBuffer();
int l = s.length();
int ch = -1;
int b, sumb = 0;
for (int i = 0, more = -1; i < l; i++) {
    switch (ch = s.charAt(i)) {
    case '%':
        ch = s.charAt(++i);
...

if (s.indexOf('\\') == -1) {
    return s;
StringBuilder result = new StringBuilder();
for (int i = 0; i < s.length(); ++i) {
    char ch = s.charAt(i);
    if (ch == '\\' && i < s.length() - 1) {
        char ch2 = s.charAt(++i);
...

String out = "";
boolean esc = false;
for (char c : s.toCharArray()) {
    if (esc) {
        if (c == 'n') {
            out += '\n';
        } else if (c == 't') {
            out += '\t';
...

if ("apos".equals(s))
    return '\'';
if ("quot".equals(s))
    return '"';
if ("lt".equals(s))
    return '<';
if ("gt".equals(s))
    return '>';
...

StringBuilder buf = new StringBuilder(s.length());
boolean inEscapeSequence = false;
for (int i = 0; i < s.length(); i++) {
    char c = s.charAt(i);
    if (inEscapeSequence) {
        if (c != ESCAPE && !hasChar(charsToEscape, c)) {
            throw new IllegalArgumentException(c + " is not a valid escape sequence character");
        buf.append(c);
        inEscapeSequence = false;
    } else if (hasChar(charsToEscape, c)) {
        throw new IllegalArgumentException(c + " must be escaped");
    } else if (c == ESCAPE) {
        inEscapeSequence = true;
    } else {
        buf.append(c);
if (inEscapeSequence) {
    throw new IllegalArgumentException("Unterminated escape sequence");
return buf.toString();

return (byte) Integer.parseInt(s.substring(i + 1, i + 3), 16);

return s.replace("\\" + toUnescape, toUnescape);