Java Utililty Methods Collection Join

if (strings.isEmpty()) {
    return "";
StringBuffer buffer = new StringBuffer();
join(strings, delimiter, buffer);
return buffer.toString();

if (strings == null) {
    throw new IllegalArgumentException("strings is null");
if (delimiter == null) {
    throw new IllegalArgumentException("delimiter is null");
StringBuilder builder = new StringBuilder();
for (Iterator<String> iterator = strings.iterator(); iterator.hasNext();) {
...

return join((String[]) strings.toArray(new String[0]), delimiter);

if (strings == null || delimiter == null) {
    return null;
StringBuffer str = new StringBuffer();
Iterator<String> iter = strings.iterator();
while (iter.hasNext()) {
    str.append(iter.next());
    if (iter.hasNext()) {
...

if (strings.isEmpty()) {
    return "";
StringBuilder sb = new StringBuilder();
for (String parameterName : strings) {
    sb.append(parameterName).append(sep);
String names = sb.substring(0, sb.length() - sep.length());
...

StringBuilder buf = new StringBuilder();
for (String str : strings) {
    buf.append(sep).append(str);
return buf.substring(sep.length());

return join(strings.toArray(new String[strings.size()]), separator);

Iterator<String> iter = strings.iterator();
StringBuilder sb = new StringBuilder();
while (iter.hasNext()) {
    sb.append(iter.next());
    if (iter.hasNext()) {
        sb.append(separator);
return sb.toString();

return join(strings.toArray(new String[strings.size()]), token);

StringBuilder bud = new StringBuilder();
for (String s : strs) {
    if (bud.length() > 0)
        bud.append(sep);
    bud.append(s);
return bud.toString();