Builder: StringJoiner.add joins parts with delimiter and wrapping

StringJoiner keeps track of the delimiter, prefix and suffix internally, so each add() call only supplies the next piece and the separators are placed automatically. The prefix and suffix appear exactly once, wrapping the whole joined sequence.

Code

StringJoiner joiner = new StringJoiner(", ", "[", "]");
joiner.add("apple").add("banana").add("cherry");
System.out.println(joiner);

Output

[apple, banana, cherry]