What consequences can arise if an element with a null value is encountered in a Stream?

In Java Stream API, encountering an element with a null value can lead to a NullPointerException, as many operations in streams do not expect null and cannot handle them.

For example, if you call the map or filter method on a stream, and the element is null, an exception will be thrown when trying to invoke a method on that element.

To avoid issues, it is recommended to:

• Exclude null elements from the stream using filter(Objects::nonNull).
• Handle null explicitly if necessary.

Example:

List<String> list = Arrays.asList("a", null, "b");

list.stream()
    .filter(Objects::nonNull) // exclude nulls
    .map(String::toUpperCase)
    .forEach(System.out::println);

Thus, having null in a stream without handling can lead to runtime errors.