Stream ofNullable(T) method in Java with examples
The ofNullable(T) method returns a sequential Stream containing a single element if this stream is non-null otherwise method returns an empty Stream. It helps to handle the null stream and NullPointerException.
Syntax:
static <T> Stream<T> ofNullable(T t)
Parameters: This method accepts a single parameter t which is the single element of which the Stream is to be returned.
Return value: This method returns a stream with a single element if the specified element is non-null, otherwise an empty stream.
Below programs illustrate ofNullable(T) method:
Program 1:
// Java program to demonstrate // Stream.ofNullable() method import java.util.stream.Stream; public class GFG { public static void main(String[] args) { // Create a stream with null Stream<String> value = Stream.ofNullable( null ); // Print values System.out.println( "Values of Stream:" ); value.forEach(System.out::println); } } |
The output printed on console of IDE is shown below.
Output:
Program 2:
// Java program to demonstrate // Stream.ofNullable method import java.util.ArrayList; import java.util.stream.Stream; public class GFG { public static void main(String[] args) { // Create ArrayList containing names ArrayList<String> list = new ArrayList<String>(); list.add( "Aman" ); list.add( "Suraj" ); list.add( "Zufaq" ); // create a stream with ArrayList Stream<ArrayList<String> > value = Stream.ofNullable(list); // print values System.out.println( "Values of Stream:" ); value.forEach(System.out::println); } } |
The output printed on console is shown below.
Output:
References: https://docs.oracle.com/javase/10/docs/api/java/util/stream/Stream.html#ofNullable(T)
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