Java Runtime Environment (JRE) 1.8, also known as Java 8, was a significant release of Java by Oracle. Here are some key points about JRE 1.8:

1. Lambda Expressions: One of the most significant features introduced in Java 8 was lambda expressions. Lambda expressions allow you to write concise and expressive code for defining inline functions or anonymous functions. They are especially useful when working with functional interfaces (interfaces with a single abstract method).

2. Streams: Java 8 introduced the Stream API, which provides a powerful way to work with sequences of data. You can use streams to perform operations like filtering, mapping, reducing, and collecting data from collections or other sources.

3. Functional Interfaces: Java 8 introduced the @FunctionalInterface annotation, which is used to indicate that an interface is meant to be used as a functional interface, i.e., an interface with a single abstract method. This annotation helps with the adoption of lambda expressions.

4. Default Methods: Java 8 allowed interfaces to have default methods with method implementations. This feature was introduced to maintain backward compatibility when adding new methods to existing interfaces.

5. New Date and Time API: Java 8 introduced the java.time package, which provides a modern date and time API that addresses the limitations and complexities of the previous java.util.Date and java.util.Calendar classes.

6. Nashorn JavaScript Engine: Java 8 included the Nashorn JavaScript engine, which allowed you to execute JavaScript code from within Java applications. It provided improved performance compared to the older Rhino engine.

7. Other Enhancements: Java 8 also included various other enhancements, such as the java.util.Optional class for handling potentially null values, the java.util.function package for functional interfaces, and improvements to the java.util.concurrent package for concurrent programming.