Java 8 – Filter a null value from a Stream

Review a Stream containing null values.

Java8Examples.java

package com.favtuts.java8.stream;

import java.util.List;
import java.util.stream.Collectors;
import java.util.stream.Stream;

public class StreamFilterNullValues {

    public static void main(String[] args) {

        Stream<String> language = Stream.of("java", "python", "node", null, "ruby", null, "php");

        //Contains null values
        List<String> result = language.collect(Collectors.toList());

        result.forEach(System.out::println);

    }
}

Output

java
python
node
null   // <--- NULL
ruby
null   // <--- NULL
php

Solution

To solve it, uses Stream.filter(x -> x!=null)

Java8Examples.java

package com.favtuts.java8.stream;

import java.util.List;
import java.util.stream.Collectors;
import java.util.stream.Stream;

public class StreamFilterNullValues {

    public static void main(String[] args) {

        Stream<String> language = Stream.of("java", "python", "node", null, "ruby", null, "php");

        // Filter to remove null values with Lambda predicate
        List<String> result = language.filter(x -> x!=null).collect(Collectors.toList());

        result.forEach(System.out::println);

    }
}

Output

java
python
node
ruby
php

Alternatively, filter with Objects::nonNull

import java.util.List;

	List<String> result = language.filter(Objects::nonNull).collect(Collectors.toList());

Download Source Code

$ git clone https://github.com/favtuts/java-core-tutorials-examples

$ cd java-basic/java8

References

1. Objects::nonNull JavaDoc
2. Java 8 Streams filter examples
3. Java 8 Collectors JavaDoc