Java String join() usage and example

Java String (String) Methods

The Java String join() method returns a new string that has the specified elements and delimiter.

Syntax of the string join() method:

String.join(CharSequence delimiter, Iterable elements)

or

String.join(CharSequence delimiter, CharSequence... elements)

Here, ... indicates that one or more CharSequence (character sequences) can be present.
Note: join() is a static method. You do not need to create a string object to call this method. Instead, we use the class name String to call this method.

join() parameters

• delimiter - Delimiter used to connect elements

• elements - Elements to be connected

join() return value

• Returns a string

Example1Java String join() and CharSequence()

class Main {
　　public static void main(String[] args) {
　　　　String result;
　　　　result = String.join("-"Java", "is", "fun";
　　　　System.out.println(result);　　//　Java-is-fun
　　}
}

Here, we passed three strings Java, is, and fun to the join() method. These strings are connected using-connected using delimiters.

Example2：Java String join() with iterable

import java.util.ArrayList;
class Main {
　　public static void main(String[] args) {
　　　　ArrayList<String> text = new ArrayList<>();
　　　　//Adding elements to the ArrayList
　　　　text.add("Java");
　　　　text.add("is");
　　　　text.add("fun");
　　　　String result;
　　　　result = String.join("-", text);
　　　　System.out.println(result);　　//　Java-is-fun
　　}
}

Here, we will create an ArrayList of String type. The elements of the ArrayList use-connected using delimiters.

Java String (String) Methods