Java Utililty Methods String Unescape

if (source == null) {
    return "";
char c;
StringBuilder buffer = new StringBuilder();
for (int i = 0, length = source.length(); i < length; i++) {
    c = source.charAt(i);
    if (c == '\\' && (i + 1 < length)) {
...

if (src == null)
    return null;
StringBuilder sb = new StringBuilder(src);
for (int ii = 0; ii < sb.length(); ii++) {
    if (sb.charAt(ii) == '\\') {
        sb.deleteCharAt(ii);
        if ((sb.charAt(ii) == 'u') || (sb.charAt(ii) == 'U')) {
            int c = (hex2dec(sb.charAt(ii + 1)) << 12) + (hex2dec(sb.charAt(ii + 2)) << 8)
...

if (src == null)
    return null;
final StringBuffer result = new StringBuffer();
for (int i = 0; i < src.length(); i++) {
    final char curChar = src.charAt(i);
    if (curChar != '\\') {
        result.append(curChar);
        continue;
...

StringBuilder sb = new StringBuilder();
sb.ensureCapacity(src.length());
int lastPos = 0;
int pos = 0;
while (lastPos < src.length()) {
    pos = src.indexOf("%", lastPos);
    if (pos == lastPos) {
        if (src.charAt(pos + 1) == 'u') {
...

if (src == null)
    return null;
StringBuffer tmp = new StringBuffer();
tmp.ensureCapacity(src.length());
int lastPos = 0, pos = 0;
char ch;
while (lastPos < src.length()) {
    pos = src.indexOf("%", lastPos);
...

StringBuilder sb = new StringBuilder(st.length());
for (int i = 0; i < st.length(); i++) {
    char ch = st.charAt(i);
    if (ch == '\\') {
        char nextChar = (i == st.length() - 1) ? '\\' : st.charAt(i + 1);
        if (nextChar >= '0' && nextChar <= '7') {
            String code = "" + nextChar;
            i++;
...

if (str == null || str.length() == 0)
    return "";
final StringBuilder result = new StringBuilder();
int len = str.length();
for (int i = 0; i < len; i++) {
    char character = str.charAt(i);
    switch (character) {
    case '_':
...

int idxS = str.indexOf('&');
if (idxS < 0) {
    return str;
StringBuilder sb = new StringBuilder(str.length());
int idxE, idx, size;
char c;
int prev = 0;
...

if (str == null) {
    return null;
int len = str.length();
if (len <= 1) {
    return str;
StringBuilder ret = new StringBuilder(len - 2);
...

if (str == null)
    return null;
if (str.length() == 0)
    return str;
for (int i = ENTITIES.length - 1; i >= 0; i--) {
    str = str.replace(ENTITIES[i][1], ENTITIES[i][0]);
return str;
...