Java String: join() Method

join() Method

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

The join() method Returns a new String composed of copies of the CharSequence elements joined together with a copy of the specified delimiter.

Note that if an element is null, then "null" is added.

Java Platform: Java SE 8

Syntax:

join(CharSequence delimiter, CharSequence... elements)

Parameter:

Return Value: a new String that is composed of the elements separated by the delimiter

Return Value Type: String

Pictorial presentation of Java String join() Method

Example: Java String join(CharSequence delimiter, CharSequence... elements) Method

The following example shows the usage of java String() method.

import java.lang.*;  
  
public class StringExample {  
  
   public static void main(String[] args) {
// join(CharSequence delimiter, CharSequence... elements)
String joined = String.join("-", "2006", "02", "15" );
System.out.println();  
   // prints length of string  
   System.out.println("Output of Join = " +joined);  

   System.out.println();  
   }  
}  

Output:

Output of Join = 2006-02-15

public static String join(CharSequence delimiter, Iterable<? extends CharSequence> elements)

Returns a new String composed of copies of the CharSequence elements joined together with a copy of the specified delimiter.

Note that if an individual element is null, then "null" is added.

Java Platform: Java SE 8

Syntax:

join(CharSequence delimiter, Iterable<? extends CharSequence> elements)

Parameter:

Return Value: a new String that is composed of the elements argument.

Return Value Type: String

Throws: NullPointerException - If delimiter or elements are null.

Example: Java String join(CharSequence delimiter, Iterable<? extends CharSequence> elements) Method

The following example shows the usage of java String() method.

import java.util.ArrayList;
import java.util.List;

public class ListJoin {

    public static void main(String[] args) {
        // join(CharSequence delimiter, Iterable<? extends CharSequence> elements)
        List<String> strList = new ArrayList<String>();
        strList.add("w3r");
        strList.add("Join");
        strList.add("Example");
        // joining with comma as delimiter
        String finalStr = String.join(";", strList);
        System.out.println();
        System.out.println("str - " + finalStr);
        System.out.println();
    }
}  

Output:

str - w3r;Join;Example

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