If you want to convert a stream of primitives int, long, double to a stream of respective wrapper objects i.e. Integer, Long, Double then Java Stream API has a boxed() method to do this job.

### boxed() method in Java

In Java stream API there are primitive specializations of Stream named IntStream, LongStream and DoubleStream and each of these interfaces has a boxed() method that returns a Stream consisting of the elements of this stream, each boxed to an Integer, Long or Double respectively.

So, to summarize in java.util.stream.IntStream interface there is a boxed() method that returns a Stream consisting of the elements of this stream, each boxed to an Integer.

In java.util.stream.LongStream interface there is a boxed() method that returns a Stream consisting of the elements of this stream, each boxed to a Long.

In java.util.stream.DoubleStream interface there is a boxed() method that returns a Stream consisting of the elements of this stream, each boxed to a Double.

boxed() is an intermediate operation.

### boxed stream Java examples

1. If you have a Stream of ints that you want to collect to a List. It wonâ€™t be possible to directly store primitive integers into a list so you will get compile time error for the following lines of code.

IntStream intStream = IntStream.of(1, 2, 3, 4, 5); // Not able to collect primitives to a list intStream.collect(Collectors.toList());

In this scenario you can use boxed() to wrap primitive ints into Integer wrapper object which can than be stored into a List.

import java.util.List; import java.util.stream.Collectors; import java.util.stream.IntStream; public class StreamBoxedDemo { public static void main(String[] args) { IntStream intStream = IntStream.of(1, 2, 3, 4, 5); List<Integer> numList = intStream.boxed().collect(Collectors.toList()); System.out.println(numList); } }

__Output__

[1, 2, 3, 4, 5]

2. Using boxed() method of LongStream to get a Stream consisting of the elements of this stream, each boxed to a Long.

public class StreamBoxedDemo { public static void main(String[] args) { List<Long> numList = LongStream.of(1, 2, 3, 4, 5) .boxed().collect(Collectors.toList()); System.out.println(numList); } }

3. Using boxed() method of DoubleStream to get a Stream consisting of the elements of this stream, each boxed to a Double.

public class StreamBoxedDemo { public static void main(String[] args) { List<Double> numList = DoubleStream.of(1, 2, 3, 4, 5) .boxed().collect(Collectors.toList()); System.out.println(numList); } }

That's all for this topic **Java Stream - boxed() With Examples**. If you have any doubt or any suggestions to make please drop a comment. Thanks!

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