Java 8 is the eighth major release of the Java programming language, which was released by Oracle Corporation in March 2014. It is a significant update that introduced several new features and enhancements to the Java platform. Some of the key features introduced in Java 8 include:

1. 1. Lambda expressions: Lambda expressions allow the representation of anonymous functions and enable functional programming in Java. They provide a concise syntax for writing code that is more expressive and easier to read.

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3. 2. Stream API: The Stream API provides a new way to process collections of data in a functional programming style. It allows developers to perform operations like filtering, mapping, reducing, and sorting on collections, making code more concise and readable.

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5. 3. Functional interfaces: Java 8 introduced a new package called java.util.function that includes functional interfaces such as Predicate, Consumer, Supplier, and Function. These interfaces are used in conjunction with lambda expressions and provide a way to work with functions as first-class citizens in Java.

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7. 4. Default methods in interfaces: Java 8 added support for default methods in interfaces, allowing methods to have default implementations. This feature enables backward compatibility when adding new methods to existing interfaces without breaking the implementations of classes that implement those interfaces.

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9. 5. Optional class: The Optional class is introduced to handle situations where a value may be absent. It helps to avoid null pointer exceptions and provides a more explicit and safer way to deal with potentially null values.

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11. 6. New Date and Time API: Java 8 introduced a new Date and Time API in the java.time package, which provides a more comprehensive and flexible approach to working with dates and times. It addresses the limitations of the older java.util.Date and java.util.Calendar classes.

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13. 7. Method references: Method references allow developers to refer to methods or constructors without invoking them. They provide a compact and readable syntax for passing methods as arguments or for implementing functional interfaces.

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15. 8. Parallel Streams: Java 8 introduced the concept of parallel streams, which allows for efficient parallel processing of collections. Parallel streams leverage multi-core processors to perform operations on data in parallel, potentially improving performance for certain types of computations.

These are some of the major features and enhancements introduced in Java 8. It has had a significant impact on the Java ecosystem and has become widely adopted by developers.