Java 8 introduced several new features and enhancements to the Java programming language. Here are some of the key features in Java 8:



Lambda Expressions: Lambda expressions allow the usage of functional programming constructs in Java. They provide a concise way to represent anonymous functions and enable functional programming techniques like map, filter, and reduce.


Stream API: The Stream API provides a new abstraction for working with collections of data. It allows you to perform aggregate operations (such as filtering, mapping, and reducing) on collections with a functional programming approach. Streams can greatly simplify code and improve performance in certain scenarios.


Default Methods: Default methods, also known as defender methods or virtual extension methods, allow interfaces to have concrete methods. This feature enables the addition of new methods to existing interfaces without breaking compatibility with the implementing classes.


Optional class: The Optional class provides a container object that may or may not contain a non-null value. It helps to avoid null pointer exceptions by enforcing explicit handling of potentially null values.


Date and Time API: Java 8 introduced a new Date and Time API that addresses many of the shortcomings of the older java.util.Date and java.util.Calendar classes. The new API is more comprehensive, immutable, and thread-safe.


Functional Interfaces: Java 8 introduced the @FunctionalInterface annotation, which helps mark interfaces that are intended to be functional interfaces. Functional interfaces have a single abstract method and can be used with lambda expressions and method references.


Method References: Method references provide a way to reference methods or constructors without invoking them. They are shorthand notations for lambda expressions, which can improve code readability.


CompletableFuture: CompletableFuture is an enhancement to the Future interface introduced in earlier versions of Java. It represents a future result that can be completed asynchronously. CompletableFuture provides a more flexible and powerful way to handle asynchronous computations.


Type Annotations: In prior versions of Java, annotations could only be applied to declarations (e.g., classes, methods, fields). Java 8 introduced the ability to apply annotations to types, which include class instances, generic types, and casts. This feature allows for more precise and expressive annotation usage and enables the creation of more powerful frameworks and tools.


Repeating Annotations: Prior to Java 8, an annotation could only be applied once to a declaration. With the introduction of repeating annotations, it became possible to apply the same annotation multiple times to the same declaration. This feature simplifies the usage of annotations that are intended to be used in a repeated manner, such as marking multiple values or multiple targets with the same annotation. To support repeating annotations, Java 8 also introduced a new container annotation called @Repeatable.


These are some of the significant features introduced in Java 8. They have had a significant impact on the way Java programs are written, enabling more expressive and efficient code.