Functional Programming Overview
What is Functional Programming?
Functional programming is a programming style focused on building programs using pure functions, avoiding shared state, and maintaining immutability. This makes the code more predictable, easier to test, and helps in writing more reliable software. Key Concepts:
Pure Functions: Functions that always produce the same output for the same input and have no side effects. Immutability: Data is never modified after creation. Instead, new data structures are created. Higher-Order Functions: Functions that take other functions as arguments or return functions as results. Benefits of Functional Programming:
Predictability: Pure functions make program behavior easier to understand. Concurrency: Immutability helps avoid issues with shared states in concurrent programs. Maintainability: Higher-order functions lead to more reusable and modular code. Lambdas in Java
What are Lambda Expressions?
Lambda expressions are a concise way to represent anonymous functions in Java, making it easier to write functional-style code. Key Points:
Syntax: (parameters) -> expression Usage: Commonly used in sorting, filtering, and mapping operations. Functional Interfaces in Java
What is a Functional Interface?
A functional interface is an interface with a single abstract method. It can be implemented using lambda expressions or method references. Key Functional Interfaces:
Predicate<T>: Represents a condition (boolean function) on an input. Function<T, R>: Represents a function that takes an argument and produces a result. Supplier<T>: Provides a result without taking any arguments. Consumer<T>: Performs an operation on an input without returning a result. Using Method References
What are Method References?
Method references provide a shorthand notation of a lambda expression to call a method, making the code cleaner and more readable. Types:
Static Method Reference: ClassName::methodName Instance Method Reference: instance::methodName Constructor Reference: ClassName::new Java Stream API
What are Streams?
Streams represent sequences of elements supporting various operations to process those elements in a functional style. Stream Operations:
Intermediate: map, filter (transform streams). Terminal: collect, forEach (produce results or side-effects). Mastering functional programming concepts and their application in Java, such as lambdas, functional interfaces, and streams, is key to writing efficient, maintainable, and scalable code. This summary introduces the core principles and tools of functional programming in Java, setting the foundation for building more robust and expressive applications. For more detailed information, refer to the Notion link: 