Java Program to Convert Integer List to Integer Array

// Java Program to Convert Integer List to Integer Array

// Importing Arrays and List classes
// from java.util package
import java.util.Arrays;
import java.util.List;

// Main class
class GFG {

    // Main driver method
    public static void main(String[] args)
    {

        // Creating an List of integer type and
        // customly inserting input elements a arguments
        List<Integer> list = Arrays.asList(1, 3, 5, 7, 9);

        // Converting Stream<Integer> to integer array
        // using stream() and mapToInt() methods, lately
        // storing them in an integer array
        int[] primitive = list.stream()
                              .mapToInt(Integer::intValue)
                              .toArray();

        // Print and display the integer array
        System.out.println(Arrays.toString(primitive));
    }
}

// Java Program to Convert Integer List to Integer Array

// Importing ArrayUtis class
// Importing Arrays and List class from java.util package
import java.util.Arrays;
import java.util.List;
import org.apache.commons.lang3.ArrayUtils;

// Main class
class GFG {

    // Main driver method
    public static void main(String[] args)
    {

        // Creating an object of List class of integer type
        List<Integer> list = Arrays.asList(1, 2, 3, 4, 5);

        // Using toPrimtive() method of Apache Common Lang's
        int[] primitive = ArrayUtils.toPrimitive(
            list.toArray(new Integer[0]));

        // Print and display the integer array
        System.out.println(Arrays.toString(primitive));
    }
}

// Java Program to Convert List to Integer Array
// Using Guava Library

// Importing required classes
import com.google.common.primitives.Ints;
import java.util.Arrays;
import java.util.List;

// Main class
class GFG {

    // Main driver method
    public static void main(String[] args)
    {

        // Creating an object of List class of integer type
        List<Integer> ints = Arrays.asList(3, 7, 8, 6, 1);

        // Converting a list of Integer to primitive integer
        // array and storing in integer array
        int[] primitive = Ints.toArray(ints);

        // Print and display the integer array via Guava
        // by converting it to string
        // via standard toString() method
        System.out.println(Arrays.toString(primitive));
    }
}