As already described, but if separator is not null, then objects
such as TaggedWord

@param separator The string used to separate Word and Tag
in TaggedWord, etc
162562
public static <T> String listToString(List<T> list, final boolean justValue,
                                        final String separator) {
    StringBuilder s = new StringBuilder();
    for (Iterator<T> wordIterator = list.iterator(); wordIterator.hasNext();) {
      T o = wordIterator.next();
      s.append(wordToString(o, justValue, separator));
      if (wordIterator.hasNext()) {
        s.append(' ');
      }
    }
    return s.toString();
  }
77786
public static List<String> splitNicely( String toSplit, String separator ) {

		if( separator == null || separator.isEmpty())
			throw new IllegalArgumentException( "The separator cannot be null or the empty string." );

		return splitNicelyWithPattern( toSplit, Pattern.quote( separator ));
	}
371212
public static <T> String join(final Collection<T> collection, final String separator) {

        if (isEmpty(collection)) {
            return "";
        }
        StringBuffer stringBuffer = new StringBuffer();
        boolean isFirstVisited = true;
        for (Object object : collection) {
            if (isFirstVisited) {
                isFirstVisited = false;
            } else {
                stringBuffer.append(separator);
            }
            stringBuffer.append(ObjectUtils.toString(object));
        }
        return stringBuffer.toString();
    }
1062157
public static String join(List<String> list, String separator) {
        if (list == null) {
            return null;
        }

        return join(list.toArray(), separator, 0, list.size());
    }
1205177
public static String join(Collection<String> collection, String separator) {
        if (collection == null) {
            return null;
        }
        return join(collection.toArray(new String[collection.size()]), separator, 0, collection.size());
    }
598033
public static String join(final Collection<?> col, final String separator) {
        return join(col, separator, ELEMENT_CONVERTER);
    }
433520
public static function remove(string $list, string $item, string $separator, string $tag = ''): string
    {
        $items = self::explode($separator, $list);
        $pos = self::pos($list, $item, $separator, $tag);
        if ($pos > -1 && isset($items[$pos])) {
            unset($items[$pos]);
        }
        return implode($separator, $items);
    }
1205378
function split(str, separator) {
    separator = separator || '';
    if (_.isString(str)) {
        return str.split(separator);
    } else {
        return str;
    }
}
755104
public static String mkString(@javax.annotation.Nonnull final String separator, final String... strs) {
    return Arrays.asList(strs).stream().collect(Collectors.joining(separator));
  }
388341
public static MutableList<String> trimmedTokensToSortedList(String string, String separator)
    {
        return StringIterate.trimmedTokensToList(string, separator).sortThis();
    }
228991
public static String join(Collection collection, String separator) {
        return join(collection, separator, true);
    }
1339405
public static String join(String separator, String[] parts) {
        StringBuilder builder = new StringBuilder();
        boolean first = true;
        for (String part : parts) {
            if (first) {
                first = false;
            } else {
                builder.append(separator);
            }
            builder.append(part);
        }
        return builder.toString();
    }
985146
public static String join(String[] strings, String separator) {
        if (strings == null || strings.length == 0) {
            return EMPTY;
        }
        StringBuilder sb = new StringBuilder();
        for (String string : strings) {
            if (isNotBlank(string)) {
                sb.append(string).append(separator);
            }
        }
        return sb.length() > 0 ? sb.substring(0, sb.length() - separator.length()) : StringUtils.EMPTY;
    }
782471
private void appendSeparator() {
    if (separators.length() == 1) {
      appendNormal(separators.charAt(0));
    } else {
      builder.append('[');
      for (int i = 0; i < separators.length(); i++) {
        appendInBracket(separators.charAt(i));
      }
      builder.append("]");
    }
  }
860484
@Nonnull
  public CSVWriter setSeparatorChar (final char cSeparator)
  {
    if (cSeparator == CCSV.NULL_CHARACTER)
      throw new UnsupportedOperationException ("The separator character must be defined!");
    m_cSeparatorChar = cSeparator;
    return this;
  }
383712
public void setMultipleSeparator(final String multipleSeparator) {
        if (multipleSeparator != null)
            attrMixin.setAttribute(MULTIPLE_SEPARATOR, multipleSeparator);
        else
            attrMixin.removeAttribute(MULTIPLE_SEPARATOR);
    }
266432
function(separator) {
		separator = separator || ".";
		var res = [];
		$.each(this.getParentList(false, true), function(i, o){
			res.push(o.getIndex() + 1);
		});
		return res.join(separator);
	}