Arrays Stream() Method in Java

Last Updated on July 15, 2024 by Abhishek Sharma

Java’s stream() method, introduced in Java 8 as part of the Stream API, is a powerful tool for functional-style operations on sequences of elements. It provides a way to process collections of objects in a declarative manner. When working with arrays, the stream() method from the Arrays class allows you to create a stream from an array, enabling you to perform a variety of operations like filtering, mapping, and reducing.

What is Java Arrays Stream() Method?

The stream() method of the Arrays class in Java is a utility method that allows you to obtain a sequential stream of elements from an array. It was introduced in Java 8 as part of the Stream API.

The stream() method is overloaded for different types of arrays, such as arrays of primitive types (int[], double[], etc.) and arrays of reference types (Object[]). When invoked on an array, it returns a sequential stream that represents the elements of the array as individual stream elements.

Syntax of Array Stream() in Java

Here’s the general syntax of the Array stream() method:

static datatypeStream stream(datatype[] array)

Here, the array represents the array from which you want to obtain the stream. The method returns a Stream object that you can use to perform various operations on the array elements, such as filtering, mapping, or reducing.

The stream() method is commonly used in combination with other stream operations to process arrays in a functional programming style, enabling concise and expressive code for array manipulation and processing.

Example of Array Stream() in Java

In this example, we demonstrate the conversion of an array, arr, into a stream of strings using the stream() method. Subsequently, we utilize the forEach method to print each element of the stream

import java.util.Arrays;
import java.util.stream.Stream;
class StudyTonight{ 
    public static void main(String args[]) 
    {  
        String[] array = { "java", "cpp", "c", "python" }; 
        Stream<String> myStream = Arrays.stream(array); 
        myStream.forEach(str -> System.out.print(str + " ")); 
    }
}

Output:

java cpp c python

Example to Convert int array to Stream

In the given example, we convert an array of integers to a stream using the stream() method. To hold the resulting stream, we employ the dedicated class IntStream, designed specifically for streams of integers. Finally, we utilize the forEach method to print each element of the converted stream of integers.

import java.util.Arrays;
import java.util.stream.IntStream;
class StudyTonight{ 
    public static void main(String args[]) 
    {  
        int[] array = {12, 41, 18, 4, 5, 31}; 
        IntStream  myStream = Arrays.stream(array); 
        myStream.forEach(str -> System.out.print(str + " ")); 		
    }
}

Output:

12 41 18 4 5 31

Conclusion
The Arrays.stream() method is a versatile tool in Java’s Stream API, enabling functional-style operations on arrays. By converting arrays into streams, you can leverage powerful features like filtering, mapping, and reducing to process data efficiently and concisely. Whether working with object arrays or primitive arrays, the Stream API provides a robust framework for modern Java development.

FAQs related to the Arrays stream method in Java

FAQs related to the Arrays stream method in Java are:

Q1: What is the Arrays.stream() method in Java?
A1: The Arrays.stream() method is a static method in the Arrays class that creates a sequential stream from an array. It enables functional-style operations on arrays.

Q2: What are the benefits of using streams with arrays?
A2: Streams provide a concise and readable way to process arrays, support parallel processing, offer a wide range of functional operations, and utilize lazy evaluation for performance optimization.

Q3: Can Arrays.stream() be used with primitive arrays?
A3: Yes, Arrays.stream() has overloaded versions to handle primitive arrays such as int, long, and double, producing IntStream, LongStream, and DoubleStream respectively.

Q4: How does the Stream API improve code readability?
A4: The Stream API uses a declarative approach to process data, allowing you to write concise and expressive code that focuses on the what rather than the how.

Q5: Can streams created from arrays be parallelized?
A5: Yes, streams can be parallelized to improve performance by leveraging multi-core processors. This can be achieved by converting a stream to a parallel stream using the parallel() method.