Java 11 introduced a convenient and null-safe method for stream creation: Stream.ofNullable(T t). This method allows developers to create a stream with a single element if it’s non-null, or an empty stream if the value is null.
This enhancement reduces boilerplate code and minimizes the risk of NullPointerException when working with optional or uncertain values in the Stream API.
🚀 Overview: Stream.ofNullable()
java
Stream.ofNullable(T t)
- Returns:
- A stream of one element if
t is not null - An empty stream if
t is null
🔍 Why Use ofNullable()?
Before Java 11, handling nullable objects with streams was verbose:
java
Stream<String> stream = myObject != null ? Stream.of(myObject) : Stream.empty();
Java 11 simplifies this with:
java
Stream<String> stream = Stream.ofNullable(myObject);
Cleaner, safer, and easier to read.
💻 Example Code
java
import java.util.stream.Stream;
public class Main {
public static void main(String[] args) {
String element = "Hello";
Stream<String> stream = Stream.ofNullable(element);
stream.forEach(System.out::println); // Outputs: Hello
String nullElement = null;
Stream<String> emptyStream = Stream.ofNullable(nullElement);
emptyStream.forEach(System.out::println); // Outputs nothing
}
}
✅ Output:
nginx
Hello
🧠 Use Cases
- Null-safe filtering: Avoid
NullPointerException during stream processing - Conditional flatMap: Return a stream from an optional value
- Data transformation pipelines: Ensure nulls don’t break the flow
📌 Summary
FeatureBenefitStream.ofNullable()Create stream from single elementHandles null safelyReturns empty stream if nullIntroduced inJava 11
Java 11’s Stream.ofNullable() method is a small but powerful addition for developers working with the Stream API. It ensures null safety, reduces code noise, and helps you write cleaner, more robust Java code.