What is StringJoiner class in Java 8?

The StringJoiner class in Java 8 constructs a sequence of characters. This sequence is separated by a delimiter and optionally starting with a supplied prefix and ending with a supplied suffix.

The following are the constructors of the StringJoiner class:

• StringJoiner(CharSequence delimiter): This constructor constructs a StringJoiner with no characters in it and with no prefix or suffix. It used the copy of the supplied delimiter.

• StringJoiner(CharSequence delimiter, CharSequence prefix, CharSequence suffix) This constructor constructs a StringJoiner with no characters in it. It uses the copies of the supplied prefix, delimiter and suffix.

The syntax is as follows:

public final class StringJoiner
extends Object

Here, class Object is the root of the class hierarchy.

To work with the StringJoiner in Java 8, import the following package:

import java.util.StringJoiner;

The following is an example to implement StringJoiner method in Java. We have used comma as the delimiter here:

Example

 Live Demo

import java.util.StringJoiner;
public class Demo {
   public static void main(String[] args) {
      StringJoiner strJoin = new StringJoiner(",");
      strJoin.add("One");
      strJoin.add("Two");
      strJoin.add("Three");
      strJoin.add("Four");
      strJoin.add("Five");
      strJoin.add("Six");
      strJoin.add("Seven");
      System.out.println(strJoin.toString());
   }
}

output

One,Two,Three,Four,Five,Six,Seven