Features of java 8

Java 8 brought a powerful new syntactic improvement in the form of lambda expressions. A lambda is an anonymous function that we can handle as a first-class language citizen. For instance, we can pass it to or return it from a method. Before Java 8, we would usually create a class for every case where we needed to encapsulate a single piece of functionality. This implied a lot of unnecessary boilerplate code to define something that served as a primitive function representation. The article java.util.function package. 3. Functional Interfaces Any interface with a SAM(Single Abstract Method) is a functional interface, and its implementation may be treated as lambda expressions. Note that Java 8's default methods are not abstract and do not count; a functional interface may still have multiple default methods. We can observe this by looking at the Function's 4. Functions The most simple and general case of a lambda is a functional interface with a method that receives one value and returns another. This function of a single argument is represented by the Function interface, which is parameterized by the types of its argument and a return value: public interface Function One of the usages of the Function type in the standard library is the Map.computeIfAbsent method. This method returns a value from a map by key, but calculates a value if a key is not already present in a map. To calculate a value, it uses the passed Function implementation: Map nameMap = new HashMap(); Inte...

In this tutorial, we're going to show the Optional class that was introduced in Java 8. The purpose of the class is to provide a type-level solution for representing optional values instead of null references. To get a deeper understanding of why we should care about the Optional class, take a look at @Test public void whenCreatesEmptyOptional_thenCorrect() By doing this, if we pass in a null reference, it doesn't throw an exception but rather returns an empty Optional object: When we have an Optional object returned from a method or created by us, we can check if there is a value in it or not with the isPresent() method: @Test public void givenOptional_whenIsPresentWorks_thenCorrect() 4. Conditional Action With ifPresent() The ifPresent() method enables us to run some code on the wrapped value if it's found to be non- null. Before Optional, we'd do: if(name != null) This code checks if the name variable is null or not before going ahead to execute some code on it. This approach is lengthy, and that's not the only problem — it's also prone to error. Indeed, what guarantees that after printing that variable, we won't use it again and then forget to perform the null check? This can result in a NullPointerException at runtime if a null value finds its way into that code. When a program fails due to input issues, it's often a result of poor programming practices. Optional makes us deal with nullable values explicitly as a way of enforcing good programming practices. Let's n...

Before Java 8, interfaces could have only public abstract methods. It was not possible to add new functionality to the existing interface without forcing all implementing classes to create an implementation of the new methods, nor was it possible to create interface methods with an implementation. Starting with Java 8, interfaces can have static and default methods that, despite being declared in an interface, have a defined behavior. Consider this method of the interface (let's call this interface Vehicle): static String producer() The static producer() method is available only through and inside of an interface. It can't be overridden by an implementing class. To call it outside the interface, the standard approach for static method call should be used: String producer = Vehicle.producer(); 2.2. Default Method default String getOverview() Assume that this interface is implemented by the class VehicleImpl. For executing the default method, an instance of this class should be created: Vehicle vehicle = new VehicleImpl(); String overview = vehicle.getOverview(); 3. Method References boolean isReal = list.stream().anyMatch(u -> User.isRealUser(u)); Let's take a closer look at lambda expression in the anyMatch() method. It just makes a call to a static method isRealUser(User user) of the User class. So, it can be substituted with a reference to a static method: boolean isReal = list.stream().anyMatch(User::isRealUser); This type of code looks much more informative. 3.2. Ref...

A Comprehensive List And Explanation Of All The Prominent Features Introduced In Java 8 Release With Examples: Java 8 release from Oracle was a revolutionary release of the world’s #1 development platform. It included a huge upgrade to the Java programming model as a whole along with the evolution of the JVM, Java language, and libraries in a coordinated manner. This release included several features for Ease of use, Productivity, Improved Polyglot Programming, Security, and Overall improved performance. What You Will Learn: • • • • • • • • • • • • • • • • Features Added To Java 8 Release Among the major changes, the following are the notable features that were added to this release. • • forEach() method in Iterable interface • Optional class, • default and static methods in Interfaces • Method references • Java Stream API for Bulk Data Operations on Collections • Java Date Time API • Collection API improvements • Concurrency API improvements • Java IO improvements • Nashorn JavaScript engine • Base64 Encode Decode • Miscellaneous Core API improvements In this tutorial, we will discuss each of these features briefly and try to explain each of them with the help of simple and easy examples. Functional Interfaces And Lambda Expressions Java 8 introduces an annotation known as @FunctionalInterface that is usually for compiler level errors. It is typically used when the interface you are using violates the contracts of functional interface. Alternatively, you can call a functi...

By: Eugen| March 18, 2020 Overview The addition of the Stream was one of the major features added to Java 8. This in-depth tutorial is an introduction to the many functionalities supported by streams, with a focus on simple, practical examples. To understand this material, you need to have a basic, working knowledge of Java 8 (lambda expressions, Introduction First of all, Java 8 Streams should not be confused with Java I/O streams (ex: FileInputStream etc); these have very little to do with each other. Simply put, streams are wrappers around a data source, allowing us to operate with that data source and making bulk processing convenient and fast. A stream does not store data and, in that sense, is not a data structure. It also never modifies the underlying data source. This functionality – java.util.stream – supports functional-style operations on streams of elements, such as map-reduce transformations on collections. Let’s now dive into few simple examples of stream creation and usage – before getting into terminology and core concepts. Java Stream Creation Let’s first obtain a stream from an existing array: private static Employee[] arrayOfEmps = Here Files.lines() returns the lines from the file as a Stream which is consumed by the getPalindrome() for further processing. getPalindrome() works on the stream, completely unaware of how the stream was generated. This also increases code reusability and simplifies unit testing. Java Streams Improvements In Java 9 Java 8 b...

In this tutorial, we're going to explore some of the JDK8-related questions that might pop up during an interview. Java 8 is a platform release packed with new language features and library classes. Most of these new features are geared towards achieving cleaner and more compact code, while some add new functionality that has never before been supported in Java. Java 8 ships with several new features, but the most significant are the following: • Lambda Expressions − a new language feature allowing us to treat actions as objects • Method References − enable us to define Lambda Expressions by referring to methods directly using their names • Optional − special wrapper class used for expressing optionality • Functional Interface– an interface with maximum one abstract method; implementation can be provided using a Lambda Expression • Default methods − give us the ability to add full implementations in interfaces besides abstract methods • Nashorn, JavaScript Engine − Java-based engine for executing and evaluating JavaScript code • Stream API − a special iterator class that allows us to process collections of objects in a functional manner • Date API − an improved, immutable JodaTime-inspired Date API Along with these new features, lots of feature enhancements are done under the hood at both the compiler and JVM level. 3. Method References (o) -> o.toString(); Can become: Object::toString(); A method reference can be identified by a double colon separating a class or object n...

Introduction (Business Case) Four years ago, after Oracle’s acquisition of Sun, back in 2010, there were a lot of questions and discussions about what is going to happen next with the Java platform and the language itself. Back then, some of the development was already done for the next release of Java, which was going to be the Java SE7, but some other things originally planned for Java SE7 were going to take longer. Soon after that, Mark Reinhold, Chief Architect of the Java Platform Group, announced that there were two possible plans for the release of Java SE7. Part one, which is Java SE7 as currently defined till the middle of 2012 and then part two, which is the Java SE8 release that has the features we couldn’t get in Java SE7 plus some other things as well. Java SE8 is defined as the JSR 337 and includes all of the features that are going into the Java platform, the Java language, the Java APIs, the JVM definitions and so on. Despite the fact that the launching of Java SE8 is very close, the specification is not quite final and there might be some minor changes until the final release, but surely not significant changes. The core part of the specification includes: • New functionality • JSR 308: Annotations on types • JSR 310: Date and Time API • JSR 335: Lambda expressions • Updated functionality • JSR 114: JDBC Rowsets • JSR 160: JMX Remote API • JSR 173: Streaming API for XML • JSR 199: Java Compiler API • JSR 206: Java API for XML Processing • JSR 221: JDBC 4.0...

• Login • Category • Academic Tutorials • Big Data & Analytics • Computer Programming • Computer Science • Databases • DevOps • Digital Marketing • Engineering Tutorials • Exams Syllabus • Famous Monuments • GATE Exams • Latest Technologies • Machine Learning • Mainframe Development • Management Tutorials • Mathematics Tutorials • Microsoft Technologies • Misc tutorials • Mobile Development • Java Technologies • Python Technologies • SAP Tutorials • Programming Scripts • Selected Reading • Software Quality • Soft Skills • Telecom Tutorials • UPSC IAS Exams • Web Development • Sports Tutorials • XML Technologies • Multi-Language • Interview Questions Job Search Java 8 is the most awaited and is a major feature release of Java programming language. This is an introductory tutorial that explains the basic-to-advanced features of Java 8 and their usage in a simple and intuitive way. Audience This tutorial will be useful for most Java developers, starting from beginners to experts. After completing this tutorial, you will find yourself at a moderate level of expertise in Java 8, from where you can take yourself to next levels. Prerequisites Knowledge of basic Java programming language is the only prerequisite for learning the concepts explained in this tutorial.