So, when we say "Programming," it includes data processing as an activity which is highly relevant for writing quality applications. In Java, Streams are an effective and resource-friendly way of dealing with any collection of data, be it an array, a list or a set. With the introduction of Java Streams in Java 8, this ability of treating data became much more efficient and functional.
Streams in java do not constitute any new data structure but rather streams in java is an abstraction that hides the complexity of dealing with data. This goal is centered around the idea of providing a highly fluent interface for data that can be appropriately processed in both sequential and parallel fashion.
This article is a beginner guide to Java Streams, their implementation, significance and the various aspects related to Streams. It is aimed to provide the readers a brief overview of how Streams in Java functions which would later help them use Streams in solving real world programming tasks effectively.
What are the Java Streams all about?
A Java stream is a linear sequence of elements which can have an impact on them in a functional way. It is possible for the programmers to handle the data from an array of lists in a readable and neat way with the help of a stream. The important aspect regarding a Stream is the fact that it already abstracts away most of the low level processes over the data and allows focusing on data processing in a more high level manner where loops are not used much if at all. Java Streams Come under `java.util` package and is viewed as a logical collection of data set of multiple elements which can be worked on within a framework.Streams are one of the unique types that can be executed in two modes either serial or in parallel. In a normal way, operations are executed one after the other, while in parallel, all the operations are separated and executed at the same time by different threads. This inbuilt parallelism of Streams makes them very useful for performance gains in data intensive applications.
Java Streams Important Characteristics
There are a few notable features about the Java Streams that allow them to perform better than other streams that revolve around manipulating collections. These attributes enhance their efficiency and performance in readability and their adaptability.1. Declarative Approach : Streams beg for a declarative style of programming where one worries about what they would want to achieve, as opposed to how they necessarily plan to achieve it. Rather than use loops and conditions, you specify the computations that will be on the data, and Java will work out the rest of the execution's logistics.
2. Laziness : One of the characteristics of Streams is that they are lazy, that is, they don't compute anything until they are desired through an invocation of a terminal operation. This is good because it means that operations will be able to be chained. For example, filtering and mapping operations wait until, for instance, `collect()` is typed in, which is when a terminal operation is executed.
3. Pipelining : Java Streams allow the chaining of methods through what is known as pipelining. This leads the developers to design a sequence of tasks such as filtering and transforming which operates on a stream of data. These tasks are performed in a pipelined manner and are completed only when each part of the program calls for it, thus, increasing the efficiency of the application.
4. Immutability : In other words, Streams don't change the initial data, they wipe out the original data and in its place create new streams or collections; retaining the data as it was, is beneficial since it minimizes side effects thus keeping streams safe.
Core Components of Java Streams
In general, Java Streams can be divided into two broad categories: Intermediate operations and Terminal operations. These operations are very significant while working with Streams and should be comprehended in detail.1. Intermediate Operations : These operations take one form of a Stream and convert it into a new form of a Stream. They are mostly lazy and are not executed until a specific terminal operation is called. Examples of intermediate operations include `filter()`, `map()`, and `sorted()`. There is no restriction on the number of stream operations used, and since intermediate operations return a new Stream, it is possible to chain many together.
2. Terminal Operations : Any set of operations that lead to termination of the stream are terminal operations. After the application of a terminal operation over a stream, that particular stream cannot be used because it is consumed. Examples of terminal operations include `forEach()`, `collect()`, `reduce()`, and `count()`. Since the terminal operations are applied, which lead to closing of the Stream, thus a Stream can be used only once.
Why Use Java Streams?
Java Developers use Java Streams because there are many advantages in comparison to the traditional ways of dealing with data. These include improved governance, more terse code and the capabilities of easy parallel processing. By using streams, developers are able to implement more sophisticated processes with less code and higher readability.Using Streams API is beneficial in that the users of this API do not need to worry about the complicated tasks of collection manipulation which are often tedious for those working with collections directly. For instance, loops used to filter and process data can now be replaced with functional style operations like filtering, mapping, and collecting, in a very few method calls.
Streams also have the advantage of being able to be processed in parallel. Java's parallel streams are an effective way of utilizing multiple processor cores which in turn help to speed up processing of data without the user having to control synchronization. With Streams, for example, a developer can easily carry out the parallelization by simply calling the `parallel()` method on a Stream, thus concurrent tasks are easier to write and use.
Common Stream Operations
Stream is rich in methods for manipulating data. Some of the most widely used methods in Java Streams are:- filter() : This intermediate operation enables processing of a stream with the exclusion of all elements that fall outside the defined limits.
- map() : The `map` method is a type of operation in which the content of the stream is replaced with a new value for each of the stream elements thereby changing elements' data type(s).
- reduce() : The `reduce()` function is an end operation which makes it possible to combine the elements of a Stream into one value or result. The value could be a sum or a product of numbers as an example.
- collect() The `collect()` function is an end operation that enables the user to gather the elements of a Stream and create a container out of them, for example, a List or a Set.
The Java stream model also includes functionality to sort data, obtain the max or min element, and obtain element counts by specific conditions in addition to these operations.
