Java 8 Features – Complete Tutorial

Java 8 is the most awaited release of Java programming language development because, in the entire history of Java, it never released that many major features. It consists of major features of Java. It is a new version of Java and was released by Oracle on 18 March 2014. Java provided support for functional programming, new Java 8 APIs, a new JavaScript engine, new Java 8 streaming API, functional interfaces, default methods, date-time API changes, etc.

Major Java 8 Features Introduced

There are a few major Java 8 features mentioned below:

• Lambda Expressions: Concise functional code using ->.
• Functional Interfaces: Single-method interfaces.
• Introduced and Improved APIs:
  1. Stream API: Efficient Data Manipulation.
  2. Date/Time API: Robust Date and Time Handling.
  3. Collection API Improvements: Enhanced Methods for Collections (e.g., removeIf, replaceAll).
  4. Concurrency API Improvements: New classes for parallel processing (e.g., CompletableFuture).
• Optional Class: Handle null values safely.
• forEach() Method in Iterable Interface: Executes an action for each element in a Collection.
• Default Methods: Evolve interfaces without breaking compatibility.
• Static Methods: Allows adding methods with default implementations to interfaces.
• Method References: Refer to methods easily.

This Java 8 tutorial covers all the important Java 8 features like Java 8 APIs, Java arrays, Java 8 ArrayList, and many more included in the Java 8 programming language. To explore detail features of Java language you can explore Java course, in this course you will get a free full beginner to advanced topics of Java programming.

Java 8 Features

• Lambda Expressions
• Functional Interfaces
• Method Reference
• Streams
• Comparable and Comparator
• Optional Class
• Date/Time API
• Miscellaneous

Lambda Expressions

Lambda Expression basically expresses an instance of the functional interface, in other words, you can say it provides a clear and concise way to represent a method of the functional interface using an expression. Lambda Expressions are added in Java 8.

• Lambda Expressions in Java 8
• Lambda Expressions Parameters
• Java Lambda Expression with Collections
• Lambda Expression Variable Capturing with Examples
• How to Create Thread using Lambda Expressions in Java?
• Serialization of Lambda Expression in Java
• Block Lambda Expressions in Java
• Match Lambdas to Interfaces in Java
• Converting ArrayList to HashMap in Java 8 using a Lambda Expression
• Check if a String Contains Only Alphabets in Java Using Lambda Expression
• Remove Elements From a List that Satisfy a Given Predicate in Java

Functional Interfaces

An interface that contains only one abstract method is known as a functional interface, but there is no restriction, you can have n number of default and static methods inside a functional interface.

• Functional Interfaces in Java
• Consumer Interface in Java with Examples
• BiConsumer Interface in Java with Examples
• Predicate Interface with Examples
• Function Interface in Java with Examples
• Supplier Interface in Java with Examples

Method Reference

Method reference is a shorthand notation of a lambda expression to call a method. There are four types of method references that are as follows:

• Static Method Reference
• Instance Method Reference of a particular object
• Instance Method Reference of an arbitrary object of a particular type
• Constructor Reference.

Example:

numList.stream().filter(n -> n > 5).sorted().forEach(System.out::println);

• Method References in Java with examples
• Converting ArrayList to HashMap using Method Reference in Java 8

Streams

Stream API is introduced in Java 8 and is used to process collections of objects with the functional style of coding using the lambda expression. So to understand what stream API is, you must have knowledge of both lambda and functional interfaces.

• Java 8 Stream
• Difference Between Streams and Collections in Java
• Implement Filter Function using Reduce in Java 8 Streams
• Java Stream API – Filters
• Parallel vs Sequential Stream in Java
• Functional Programming in Java 8+ using the Stream API with Example
• Intermediate Methods of Stream in Java
• Difference Between map() And flatMap() In Java Stream
• Array to Stream in Java
• 10 Ways to Create a Stream in Java
• How to Print Elements of a Stream in Java 8
• Collecting a Stream to an Immutable Collection in Java
• Comparing Streams to Loops in Java
• Why You Need to Close the Java Streams in Finally Block?
• Convert an Iterable to Stream in Java
• Convert an Iterator to Stream in Java
• Difference Between Stream.of() and Arrays.stream() method in Java
• Convert Stream to Set in Java
• Convert a Set to Stream in Java
• Streams on Arrays in Java 8

Java Stream Programs

Java Streams provide a powerful and expressive way to process sequences of elements in Java, enabling functional-style operations on collections of data. The Stream API, introduced in Java 8, facilitates efficient data manipulation and transformation using a sequence of operations that can be performed in parallel or sequentially

. Java Stream Programs will give a clear view to the topic:

• Program to Convert a Map to a Stream in Java
• Program to Convert Boxed Array to Stream in Java
• Program to Convert Primitive Array to Stream in Java
• Program to Convert a Set to Stream in Java using Generics
• Program to Convert List to Stream in Java
• Program to Convert Stream to an Array in Java
• How to get Slice of a Stream in Java
• Flattening Nested Collections in Java
• How to Convert a Stream into a Map in Java
• Find the First Element of a Stream in Java
• Find the Last Element of a Stream in Java
• How to Find Duplicate Elements in a Stream in Java
• Count the Occurrence of a Given Character in a String Using Stream API in Java
• Reverse Elements of a Parallel Stream in Java
• How to Get ArrayList From Stream in Java 8
• Generate Infinite Stream of Double in Java
• Generate Infinite Stream of Integers in Java
• Program to Iterate over a Stream with Indices in Java 8
• Flatten a Stream of Arrays in Java using forEach loop
• Flatten a Stream of Lists in Java using forEach loop
• Flatten a Stream of Map in Java using forEach loop
• Convert a String to a List of Characters in Java
• Initialize a List in a Single Line with a Specified Value using Java Stream

Java Stream Methods