Java Guava | Bytes.toArray() method with Examples

The toArray() method of Bytes Class in the Guava library is used to convert the byte values, passed as the parameter to this method, into a Byte Array. These byte values are passed as a Collection to this method. This method returns a Byte array.

Syntax:

public static byte[] toArray(Collection<? extends Number> collection)

Parameters: This method accepts a mandatory parameter collection which is the collection of byte values to be converted in to a Byte array.

Return Value: This method returns a byte 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 code to show implementation of 
// Guava's Bytes.toArray() method 

import com.google.common.primitives.Bytes; 

import java.util.Arrays; 

import java.util.List; 

class GFG { 

    // Driver's code 

    public static void main(String[] args) 

    { 

        // Creating a List of Bytes 

        List<Byte> myList 

            = Arrays.asList((byte)1, 

                            (byte)2, 

                            (byte)3, 

                            (byte)4, 

                            (byte)5); 

        // Using Bytes.toArray() method to convert 

        // a List or Set of Byte to an array 

        // of Byte 

        byte[] arr = Bytes.toArray(myList); 

        // Displaying an array containing each 

        // value of collection, 

        // converted to a byte value 

        System.out.println(Arrays.toString(arr)); 

    } 
}

Output:

[1, 2, 3, 4, 5]

Example 2:

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

import com.google.common.primitives.Bytes; 

import java.util.Arrays; 

import java.util.List; 

class GFG { 

    // Driver's code 

    public static void main(String[] args) 

    { 

        try { 

            // Creating a List of Bytes 

            List<Byte> myList 

                = Arrays.asList((byte)2, 

                                (byte)4, 

                                null); 

            // Using Bytes.toArray() method 

            // to convert a List or Set of Byte 

            // to an array of Byte. 

            // This should raise "NullPointerException" 

            // as the collection contains 

            // "null" as an element 

            byte[] arr = Bytes.toArray(myList); 

            // Displaying an array containing each 

            // value of collection, 

            // converted to a byte value 

            System.out.println(Arrays.toString(arr)); 

        } 

        catch (Exception e) { 

            System.out.println(e); 

        } 

    } 
}