Functional programming in Java was significantly enhanced with the introduction of Java 8. This programming paradigm emphasizes “what to solve” rather than “how to solve,” contrasting with the procedural approach. In functional programming, functions are first-class citizens, meaning they can be assigned to variables, passed as parameters, and returned from other functions. This allows for a more declarative style of programming, focusing on the evaluation of mathematical functions rather than changing state or mutable data ³⁵.

Java 8 introduced several key features to support functional programming, including lambda expressions, the Stream API, and the Optional class. Lambda expressions allow for concise representation of functions, while the Stream API enables functional-style operations on collections, such as filtering and mapping. The Optional class helps in handling null values more gracefully, promoting safer code practices ⁴².

Overall, functional programming in Java provides developers with powerful tools to write cleaner, more efficient, and maintainable code.