Here are some key aspects of Java SE 8:

1. Lambda Expressions: Java SE 8 introduced lambda expressions, which are a powerful feature for writing more concise and expressive code. Lambda expressions enable the functional programming paradigm in Java and are commonly used with the Stream API and functional interfaces.

2. Stream API: The Stream API is a key feature of Java SE 8 that provides a high-level abstraction for working with sequences of data, such as collections or arrays. It allows developers to perform operations like filtering, mapping, and reducing data in a functional and declarative style.

3. Default Methods: Java SE 8 introduced the concept of default methods in interfaces. Default methods provide a way to add new methods to existing interfaces without breaking compatibility with implementing classes.

4. Functional Interfaces: Java SE 8 introduced the @FunctionalInterface annotation to indicate that an interface is intended to be used as a functional interface. Functional interfaces have a single abstract method and can be used with lambda expressions.

5. New Date and Time API: Java SE 8 introduced the Date and Time API (java.time package) to address the limitations of the older Date and Calendar classes. It provides a more comprehensive and reliable way to work with dates and times.

6. Nashorn JavaScript Engine: Java SE 8 includes the Nashorn JavaScript engine, which provides a high-performance runtime for executing JavaScript code within Java applications.

7. Method References: Java SE 8 introduced method references, which allow you to refer to methods using a concise syntax. Method references are often used in conjunction with lambda expressions to improve code readability.

8. Functional Programming Features: With lambda expressions and the Stream API, Java SE 8 embraced functional programming principles, making it easier to write code that is more concise, readable, and expressive.

9. Compact Profiles: Java SE 8 introduced compact profiles, which are subsets of the Java SE platform optimized for embedded and resource-constrained environments. They allow for more efficient use of Java in specialized applications.