Java 8 and later

Using StringJoiner class, and forEach method :

StringJoiner joiner = new StringJoiner(",");list.forEach(item -> joiner.add(item.toString());return joiner.toString();

Using Stream, and Collectors:

return list.stream().       map(Object::toString).       collect(Collectors.joining(",")).toString();

Java 7 and earlier

See also #285523

String delim = "";for (Item i : list) {    sb.append(delim).append(i);    delim = ",";}

org.apache.commons.lang3.StringUtils.join(list,",");

Java 8 provides several new ways to do this:

• The join method on String.
• A joining collector for streams from the Collectors class.
• The StringJoiner class.

Example:

// Util method for strings and other char sequencesList<String> strs = Arrays.asList("1", "2", "3");String listStr1 = String.join(",", strs);// For any type using streams and collectorsList<Object> objs = Arrays.asList(1, 2, 3);String listStr2 = objs.stream()    .map(Object::toString)    .collect(joining(",", "[", "]"));// Using the new StringJoiner classStringJoiner joiner = new StringJoiner(", ", "[", "]");joiner.setEmptyValue("<empty>");for (Integer i : objs) {  joiner.add(i.toString());}String listStr3 = joiner.toString();

The approach using streams assumes import static java.util.stream.Collectors.joining;.