Java StringJoiner - setEmptyValue() Method

The java.util.StringJoiner.setEmptyValue() method is used to set the sequence of characters to be used when determining the string representation of this StringJoiner and no elements have been added yet, that is, when it is empty. A copy of the emptyValue parameter is made for this purpose. Note that once an add method has been called, the StringJoiner is no longer considered empty, even if the element(s) added correspond to the empty String.

Syntax

public StringJoiner setEmptyValue(CharSequence emptyValue)

Parameters

Return Value

Returns this StringJoiner itself so the calls may be chained.

Exception

Throws NullPointerException, when the emptyValue parameter is null.

Example:

The example below shows how to use java.util.StringJoiner.setEmptyValue() method.

import java.util.*;

public class MyClass {
  public static void main(String[] args) {
    //creating a StringJoiner object
    StringJoiner joinNames = new StringJoiner(", ", "[", "]");

    //setting default empty value   
    joinNames.setEmptyValue("It is empty."); 

    //printing joinNames 
    System.out.println("joinNames contains: " + joinNames);

    //Adding values to joinNames
    joinNames.add("John");
    joinNames.add("Marry");
    joinNames.add("Kim");

    //printing joinNames 
    System.out.println("joinNames contains: " + joinNames);
  }
}

The output of the above code will be:

joinNames contains: It is empty.
joinNames contains: [John, Marry, Kim]