Java Guava | Chars.toArray() method with Examples

Last Updated : 31 Jan, 2019

The toArray() method of Chars Class in the Guava library is used to convert the char values, passed as the parameter to this method, into a Char Array. These char values are passed as a Collection to this method. This method returns a Char array. Syntax:

public static char[] toArray(Collection<Character> collection)

Parameters: This method accepts a mandatory parameter collection which is the collection of char values to be converted in to a Char array. Return Value: This method returns a char array containing the same values as a collection, in the same order. Exceptions: This method throws NullPointerException if the passed collection or any of its elements is null. Below programs illustrate the use of toArray() method: Example 1 :

Java

// Java code to show implementation of
// Guava's Chars.toArray() method

import com.google.common.primitives.Chars;
import java.util.Arrays;
import java.util.List;

class GFG {

    // Driver's code
    public static void main(String[] args)
    {

        // Creating a List of Chars
        List<Character> myList
            = Arrays.asList('G', 'E', 'E', 'K', 'S');

        // Using Chars.toArray() method to convert
        // a List or Set of Char to an array of Char
        char[] arr = Chars.toArray(myList);

        // Displaying an array containing each
        // value of collection,
        // converted to a char value
        System.out.println(Arrays.toString(arr));
    }
}

Output:

[G, E, E, K, S]

Example 2 :

Java

// Java code to show implementation of
// Guava's Chars.toArray() method

import com.google.common.primitives.Chars;
import java.util.Arrays;
import java.util.List;

class GFG {

    // Driver's code
    public static void main(String[] args)
    {

        try {
            // Creating a List of Chars
            List<Character> myList
                = Arrays.asList('a', 'b', null);

            // Using Chars.toArray() method
            // to convert a List or Set of Char
            // to an array of Char.
            // This should raise "NullPointerException"
            // as the collection contains "null"
            // as an element
            char[] arr = Chars.toArray(myList);

            // Displaying an array containing each
            // value of collection,
            // converted to a char value
            System.out.println(Arrays
                                   .toString(arr));
        }
        catch (Exception e) {
            System.out.println(e);
        }
    }
}