The join()
method returns a new string with the given elements joined with the specified delimiter.
Example
class Main {
public static void main(String[] args) {
String str1 = "I";
String str2 = "love";
String str3 = "Java";
// join strings with space between them
String joinedStr = String.join(" ", str1, str2, str3);
System.out.println(joinedStr);
}
}
// Output: I love Java
Syntax of join()
The syntax of the string join()
method is either:
String.join(CharSequence delimiter,
Iterable elements)
or
String.join(CharSequence delimiter,
CharSequence... elements)
Here, ...
signifies there can be one or more CharSequence
.
Note: join()
is a static method. You do not need to create a string object to call this method. Rather, we call the method using the class name String
.
join() Parameters
The join()
method takes two parameters.
- delimiter - the delimiter to be joined with the elements
- elements - elements to be joined
Notes:
- You can pass any class that implements
CharSequence
tojoin()
. - If an iterable is passed, its elements will be joined. The iterable must implement
CharSequence
. - String, StringBuffer, CharBuffer etc. are CharSequence as these classes implement it.
join() Return Value
- returns a string
Example 1: Java String join() With 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 have passed three strings Java
, is
and fun
to the join()
method. These strings are joined using the -
delimiter.
Example 2: 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, an ArrayList
of String
type is created. The elements of array list are joined using the -
delimiter.