142-java-functional-programming

Identify and apply functional programming principles in Java to improve immutability, expressiveness, and maintainability.

Prerequisites: Run ./mvnw compile or mvn compile before applying any changes. If compilation fails, stop immediately — do not proceed until the project compiles successfully. Also verify that the project's maven-compiler-plugin source/target supports the Java features being used.

Core areas: Immutable objects and Records (JEP 395), pure functions free of side effects, functional interfaces (Function, Predicate, Consumer, Supplier) and custom @FunctionalInterface types, lambda expressions and method references, Stream API (filter/map/reduce pipelines, parallel streams, toUnmodifiable collectors), Optional idiomatic usage (map/flatMap/filter/orElse over isPresent()+get()), function compositi...

当您需要在 Java 中应用函数式编程原理时使用 - 包括编写不可变对象和记录、纯函数、函数式接口、lambda 表达式、流 API 管道、空安全性的可选、函数组合、高阶函数、instanceof 和 switch 的模式匹配、用于受控层次结构的密封类/接口、用于自定义操作的流收集器、柯里化/部分应用、效果边界分离和并发安全函数模式。 java 技能项目的一部分 来源：jabrena/cursor-rules-java。