ByteArrayOutputStream writeBytes(byte[]) in Java

writeBytes(byte[]): This method is available in the java.io.ByteArrayOutputStream class of Java.

Syntax:

void java.io.ByteArrayOutputStream.writeBytes(byte[] b)

This method takes one argument. This method writes the complete contents of the specified byte array to this ByteArrayOutputStream.

Parameters: One parameter is required for this method.

b: the data.

Returns: NA

Throws:

NullPointerException - if b is null.

Approach 1: When no exception

Java

import java.io.ByteArrayOutputStream;
import java.io.IOException;

public class ByteArrayOutputStreamwrite3 {
    public static void main(String[] args) throws IOException {

        ByteArrayOutputStream byteArrayOutputStream =
                           new ByteArrayOutputStream();

        byte b[] = { '1', '2', '3', '4' };
        byteArrayOutputStream.writeBytes(b);
        System.out.println(byteArrayOutputStream.toString());
        byteArrayOutputStream.close();
    }
}

Output:

1234

Approach 2: NullPointerException

Java

import java.io.ByteArrayOutputStream;
import java.io.IOException;

public class ByteArrayOutputStreamwrite3 {
    public static void main(String[] args) throws IOException {

        ByteArrayOutputStream byteArrayOutputStream = 
                         new ByteArrayOutputStream();

        byte b[] = null;
        byteArrayOutputStream.writeBytes(b);
        System.out.println(byteArrayOutputStream.toString());
        byteArrayOutputStream.close();
    }
}

Output:

Exception in thread "main" java.lang.NullPointerException: Cannot read the array length because "b" is null
	at java.base/java.io.ByteArrayOutputStream.writeBytes(ByteArrayOutputStream.java:148)