Java Utililty Methods List Join

int size = strings.size();
if (size == 0) {
    return ""; 
StringBuilder sb = new StringBuilder(strings.size() * strings.get(0).length());
int index = 0;
int lastIndex = size - 1;
for (String string : strings) {
...

StringBuilder sb = new StringBuilder();
for (Iterator<String> i = strings.iterator(); i.hasNext();) {
    sb.append(i.next()).append(i.hasNext() ? separator : "");
return sb.toString();

if (strings == null) {
    return "";
StringBuffer sb = new StringBuffer();
for (int i = 0, m = strings.size(); i < m; i++) {
    String string = strings.get(i);
    if (string == null) {
        string = "";
...

if (stringsToJoin == null) {
    return null;
StringBuilder sb = new StringBuilder(stringsToJoin.size() * 30);
for (int i = 0; i < stringsToJoin.size(); i++) {
    if (i > 0) {
        sb.append(delimiter);
    addToBuilderAndEscapeDelimiter(stringsToJoin.get(i), delimiter, sb);
return sb.toString();

if (strList == null || strList.isEmpty())
    return "";
if (strList.size() == 1)
    return strList.get(0);
StringBuilder sb = new StringBuilder();
for (String s : strList) {
    if (sb.length() > 0)
        sb.append(separator);
...

StringBuilder builder = new StringBuilder();
for (final Iterator<String> i = strList.iterator(); i.hasNext();) {
    final String s = i.next();
    builder.append(s);
    if (i.hasNext())
        builder.append(sep);
return builder.toString();
...

StringBuilder result = new StringBuilder();
if (!tokens.isEmpty()) {
    result.append(tokens.get(0));
for (String token : tokens.subList(1, tokens.size())) {
    result.append(sep);
    result.append(token);
return result.toString();

return (join(tokens, null, null, separator));

StringBuilder sb = new StringBuilder();
if (tokens != null && separator != null) {
    for (String token : tokens) {
        if (sb.length() > 0) {
            sb.append(separator);
        sb.append(token);
return sb.toString();

return join(values, ", ");