What happens if you use the Java 9 List.of() method with null elements?

Java MCQ: What happens if you use the Java 9 List.of() method with null elements?

Answer:

Explanation:

Using the List.of() method introduced in Java 9 with null elements will result in a NullPointerException. The List.of() method is designed to create an immutable list, and one of the constraints is that it does not allow null elements. Attempting to create a list with null elements using List.of() will immediately throw a NullPointerException.

Here’s an example that demonstrates this behavior:

import java.util.List;

public class ListOfNullExample {
    public static void main(String[] args) {
        // This will throw NullPointerException because the list contains null
        List<String> list = List.of("John", null, "Jane");
    }
}

In this example, the List.of("John", null, "Jane") statement will throw a NullPointerException because the list contains a null element. This strict enforcement of non-null elements ensures the immutability and consistency of the list created with List.of().

Reference links:

https://www.rameshfadatare.com/learn-java-programming/
https://www.javaguides.net/p/java-tutorial-learn-java-programming.html