Java Utililty Methods Collection Join

if (c.isEmpty())
    return "";
StringBuilder sb = new StringBuilder();
Iterator i = c.iterator();
sb.append(i.next());
while (i.hasNext()) {
    sb.append(separator);
    sb.append(i.next());
...

StringBuilder sb = new StringBuilder();
for (Object item : items)
    if (item != null)
        sb.append(separator).append(item);
return sb.substring(separator.length());

StringBuilder result = new StringBuilder((separator.length() + 1) * items.size());
int i = 0;
for (Object item : items) {
    if (i > 0)
        result.append(separator);
    result.append(item.toString());
    i++;
return result.toString();

StringBuilder builder = new StringBuilder();
String sep = "";
if (objs != null) {
    for (Object o : objs) {
        builder.append(sep).append(String.valueOf(o));
        sep = separator;
return builder.toString();

StringBuilder builder = new StringBuilder(parts.size() * 16);
boolean first = true;
for (String line : parts) {
    if (!first) {
        builder.append(separator);
    if (line != null) {
        builder.append(line);
...

if (separator == null) {
    throw new IllegalArgumentException("separator cannot be null");
if (strings != null && strings.size() > 0) {
    StringBuilder sb = new StringBuilder();
    for (String s : strings) {
        sb.append(separator);
        sb.append(s);
...

if (objects.isEmpty()) {
    return "";
Iterator<T> iter = objects.iterator();
final StringBuilder ret = new StringBuilder(iter.next().toString());
while (iter.hasNext()) {
    ret.append(separator);
    ret.append(iter.next().toString());
...

return join(new StringBuilder(), separator, values).toString();

StringBuffer sb = new StringBuffer();
for (Iterator iter = strings.iterator(); iter.hasNext();) {
    sb.append(iter.next());
    if (iter.hasNext()) {
        sb.append(token);
return (sb.toString());
...