Functional & Reactive
for Core Java.
A nano lib of focused, battle-tested primitives — Result<T>, checked functions, async pipelines,
tuples, pattern matching and memoization — all sitting on top of plain Java 8+.
<dependency>
<groupId>com.svenruppert</groupId>
<artifactId>functional-reactive</artifactId>
<version>06.01.01</version>
</dependency>What's inside
Small, composable building blocks that play nicely with the JDK you already have.
Result<T>
A Success/Failure type with map, flatMap, thenCombine and ifPresentOrElse. Optional, but for errors.
Read more →Checked Functions
Functional interfaces that can throw — and lift cleanly into Result.
Read more →CompletableFutureQueue
Define async pipelines as ordered transformations on top of CompletableFuture.
Read more →Tuples (Pair…Sept)
Type-safe N-ary tuples with proper equals/hashCode — drop-in for ad-hoc grouping.
Read more →Pattern Matching
Case for declarative branching — no fall-through, no boilerplate.
Read more →Memoizer
Cache the result of any pure function, mono- bi- or tri-arity.
Read more →Designed for production
- ✓ In production use for over a decade.
- ✓ Zero runtime dependencies beyond the JDK.
- ✓ JDK 8 baseline, optional
module-info.javafor JDK 9+. - ✓ Licensed under EUPL 1.2 — friendly to commercial use.
Result<User> user = repository.findById(id);
String greeting = user
.map(User::getName)
.map(name -> "Hello, " + name)
.orElse("Hello, stranger");Functional Java done right
Workshops, architecture reviews and pair-programming for teams adopting functional patterns on the JVM.
Learn more →Support continued maintenance
functional-reactive is open source. Sponsoring keeps releases predictable and roadmaps public.
Become a sponsor →