Java Utililty Methods Regex String Replace

if (!hasLength(inString) || !hasLength(oldPattern) || newPattern == null) {
    return inString;
StringBuilder sb = new StringBuilder();
int pos = 0; 
int index = inString.indexOf(oldPattern);
int patLen = oldPattern.length();
while (index >= 0) {
...

Pattern pattern = Pattern.compile(regexp);
Matcher matcher = pattern.matcher(line);
while (matcher.find()) {
    line = line.replace(matcher.group(), replacement);
return line;

Matcher matcher = messagePattern.matcher(message);
StringBuffer sb = new StringBuffer();
while (matcher.find()) {
    String key = matcher.group(1);
    try {
        matcher.appendReplacement(sb, bundle.getString(key));
    } catch (MissingResourceException e) {
        matcher.appendReplacement(sb, key);
...

for (int i = 0; i < operateOn.length; i++) {
    Pattern patternOutput = Pattern.compile(from);
    Matcher matcherOutput = patternOutput.matcher(operateOn[i]);
    operateOn[i] = matcherOutput.replaceFirst(to);

return Pattern.compile(target.toString(), Pattern.LITERAL).matcher(original)
        .replaceAll(quoteReplacement(replacement.toString()));

return concatWithSeparator(explode(s, pattern).toArray(new String[0]), replace);

Matcher m = pattern.matcher(s);
if (m.find()) {
    StringBuilder sb = new StringBuilder((int) (s.length() * 1.5));
    int start = 0;
    do {
        if (start < m.start()) {
            sb.append(s, start, m.start());
        sb.append(func.apply(m));
        start = m.end();
    } while (m.find());
    if (start < s.length()) {
        sb.append(s, start, s.length());
    return sb.toString();
return s;

String regex = "\\$\\w+\\W|\\$\\{[^}]+\\}";
Pattern pattern = Pattern.compile(regex);
Matcher m = pattern.matcher(s);
while (m.find()) {
    String temp = m.group();
    String key = null;
    if (temp.indexOf("{") != -1) {
        key = temp.substring(temp.indexOf("{") + 1, temp.length() - 1);
...

return pattern.matcher(s1).replaceAll(s2);

char[] chars = source.toCharArray();
char[] prefixChars = prefix.toCharArray();
char[] suffixChars = suffix.toCharArray();
StringBuffer result = new StringBuffer();
int index = 0;
boolean findPrefix = false;
boolean findSuffix = false;
int prefixIndex = -1;
...