Open-source alternatives to Advanced Java

NATS Server is a high-performance, lightweight messaging system designed for cloud-native applications, edge computing, and distributed microservices. It functions as a distributed publish-subscribe broker that routes messages using hierarchical, dot-separated subject strings, enabling decoupled communication between services without requiring centralized broker lookups. The system supports core messaging patterns including asynchronous publish-subscribe, request-reply, and load-balanced queue processing. The platform distinguishes itself through a decentralized architecture that eliminates t

This project is a reference implementation of microservices architectures using the Spring Cloud ecosystem. It provides a set of example services that demonstrate the construction of distributed systems through automated service discovery, dynamic routing, and shared configuration. The implementation covers core distributed patterns, including a service discovery system for tracking network components and an API gateway for orchestrating incoming traffic. It features a centralized configuration manager to propagate application settings across multiple instances and a distributed tracing syste

This project is a distributed systems design framework and architecture guide. It provides technical resources for designing, deploying, and coordinating independent network services. The framework establishes a structured methodology for migrating monolithic applications into decentralized services by separating frontend and backend concerns. It serves as a reference for event-driven architecture, focusing on maintaining data consistency across network boundaries using event sourcing and local transaction records. The project covers a broad range of capabilities including distributed servic

Hazelcast is a distributed data platform that combines an in-memory data grid with a stream processing engine to support real-time analytics and event-driven applications. It functions as a partitioned, distributed key-value store that replicates data across cluster nodes to provide low-latency access and high availability. The platform also serves as a distributed SQL query engine, allowing users to execute standard SQL statements against both in-memory datasets and external data sources. What distinguishes Hazelcast is its use of a distributed consensus subsystem to maintain strongly consis

This project is a comprehensive knowledge base and study resource designed for mastering technical interviews. It provides structured guides, roadmaps, and curricula focused on data structures, algorithms, system design, and frontend engineering to help candidates prepare for software engineering screenings. The repository distinguishes itself by offering a holistic approach to professional advancement. Beyond technical drills, it includes a career development handbook covering resume optimization, salary benchmarking, and strategic negotiation coaching. It also provides detailed methodologie

ShardingSphere is a distributed SQL database middleware that provides sharding, read-write splitting, and distributed transaction management for relational databases. It functions as a layer that intercepts SQL queries to distribute data across multiple physical database instances for horizontal scaling. The project is distinguished by its ability to operate as either a standalone transparent database proxy or via direct integration as a JDBC driver. It features a SQL dialect translator that parses queries into abstract syntax trees to convert syntax between different database engines, enabli

brpc is a high-performance C++ RPC framework and network programming library designed for building distributed systems. It functions as a multi-protocol RPC server capable of hosting and detecting multiple communication protocols, including gRPC, Thrift, HTTP, Redis, and Memcached, on a single TCP port. The project distinguishes itself through high-throughput data transport and memory efficiency, utilizing RDMA-based transport to bypass the kernel TCP stack and zero-copy memory management to eliminate data duplication. It also implements the Raft algorithm for consensus-based state replicatio

VictoriaMetrics is a high-performance, scalable time series database and observability platform designed for long-term storage and analysis of metric, log, and trace data. It functions as a unified backend for monitoring ecosystems, offering full compatibility with industry-standard protocols and query languages. The system is built to handle massive data volumes through a distributed architecture that supports horizontal scaling and efficient data lifecycle management. The platform distinguishes itself through a storage engine that utilizes consistent hashing for data sharding and log-struct

This project is a reference implementation of a distributed system built using Spring Cloud Alibaba, Spring Boot, and JDK 17. It serves as a comprehensive model for implementing a microservices architecture. The system integrates a wide range of distributed patterns, including global transaction coordination for data consistency, OAuth2 and JWT for identity management, and Kubernetes-based container orchestration. It features a dedicated observability stack for distributed request tracing, log aggregation, and service health monitoring. The implementation covers several functional domains, i

SpringBlade is a development framework and platform designed for building multi-tenant SaaS applications. It provides a comprehensive scaffold for both Spring Cloud microservices and monolithic Spring Boot architectures, enabling the rapid construction of enterprise-grade software. The platform distinguishes itself through integrated LLM orchestration and industrial IoT management. It features an LLM orchestration platform that combines large language models with knowledge bases and visual AI agent workflows, alongside an IoT hub for device connectivity, state synchronization, and edge flow o

This project is a comprehensive educational resource and study guide focused on distributed systems architecture and backend infrastructure design. It provides a structured curriculum for mastering the principles of scalability, reliability, and performance required to design complex software systems. The repository distinguishes itself by offering a methodical approach to technical interview preparation, incorporating design patterns, architectural trade-offs, and spaced repetition tools to help users retain complex concepts. It emphasizes constraint-driven analysis, teaching users how to ev

This project is a comprehensive educational resource focused on the principles, patterns, and trade-offs required to design scalable, reliable, and high-performance distributed systems. It provides a structured curriculum that covers the fundamental architectural strategies necessary for building modern software infrastructure, ranging from high-level system decomposition to low-level networking and data management. The repository distinguishes itself by offering deep dives into complex architectural patterns, such as microservices-based decomposition, event-driven communication, and command-

Olric is a distributed data grid and in-memory key-value store that partitions and replicates data across a cluster of servers. It serves as a shared memory system for managing distributed maps, performing atomic operations, and acting as an in-memory data cache. The system provides a distributed locking mechanism for concurrency control and a pub-sub messaging system that broadcasts and routes messages over named channels across the cluster. The platform covers wide-ranging capabilities including cluster management and orchestration, data replication with configurable quorums, and automated

Hystrix is a latency and fault tolerance library designed to prevent cascading failures in distributed systems. It functions as a circuit breaker implementation that monitors failure thresholds and opens circuits to isolate remote calls when downstream services degrade. The project distinguishes itself by providing multiple isolation mechanisms, utilizing dedicated thread pools and semaphores to ensure that latency in one dependency does not saturate the entire system. It also features a request collapsing and batching engine that groups concurrent calls into single executions to reduce the t

This project is an integration framework that bootstraps Apache Dubbo remote procedure call services within Spring Boot applications. It serves as a microservice communication framework that enables the implementation of RPC services, service discovery, and distributed governance through automated configuration. The project distinguishes itself by providing a cross-language RPC bridge, allowing services written in different languages to communicate via standards such as gRPC and Protobuf. It further enables the exposure of backend microservices as REST endpoints using the Triple protocol for

SpringCloud-Learning is an educational project that demonstrates how to build microservices using Spring Cloud, covering the core patterns of service discovery, centralized configuration management, and API gateway routing. The project provides hands-on examples for registering and discovering microservice instances with Nacos, Eureka, or Consul, and for routing external API requests through Spring Cloud Gateway with support for filters and load balancing. The tutorials explore service resilience through circuit breakers and rate limiting with Sentinel and Hystrix, including custom fallback l

phpredis is a C-based native extension that bridges PHP applications with Redis servers for high-performance data storage and retrieval. It serves as an interface for manipulating strings, hashes, lists, sets, and sorted sets while providing a direct path for executing Redis commands and server-side scripts. The extension provides comprehensive support for distributed environments and high availability. It interfaces with Redis Cluster to distribute data across multiple nodes using hash slots and manages Redis Sentinel for service discovery and automatic failover. It also enables shared state

rpcx is a high-performance remote procedure call framework for building scalable microservices in Go. It functions as a binary protocol RPC system and a service mesh, providing the necessary infrastructure for low-latency inter-service communication and distributed cloud environments. The project features a cross-language service gateway that provides an HTTP entry point, allowing clients written in any programming language to invoke Go remote services via protocol translation. It also includes a specialized RPC traffic analyzer for capturing and analyzing binary packets to debug network comm

Spring Cloud Alibaba is a suite of libraries designed to connect distributed Java applications to Alibaba cloud middleware and infrastructure services. It provides a comprehensive set of tools for messaging, configuration, task scheduling, transaction coordination, and service discovery. The project implements distributed infrastructure capabilities including a transaction coordinator for maintaining data consistency across multiple services and a configuration manager for storing external settings in a centralized cloud repository with automatic updates. It includes a distributed job schedul

Finagle is a distributed service mesh and fault-tolerant remote procedure call framework. It provides a protocol-agnostic network library that implements a consistent interface for different network standards, including HTTP and Thrift. The project distinguishes itself by integrating a fault tolerance library that prevents cascading failures through circuit breaking and timeout management. It also implements a distributed tracing system to track requests across network boundaries and visualize call graphs. The framework covers several core capability areas, including dynamic service discover

Vitess is a database clustering system for horizontal scaling of MySQL. It functions as a middleware layer that abstracts complex sharding and physical topology, allowing applications to interact with a distributed database environment through a unified interface. By intercepting and routing SQL queries across multiple shards, it enables large-scale data management while maintaining the appearance of a single database instance. The platform distinguishes itself through its ability to perform online schema migrations and distributed transaction coordination without requiring application downti

Dubbo is a Java RPC framework and microservices governance platform designed for high-performance remote procedure calls in distributed architectures. It provides the foundational components necessary to connect distributed services across a network, including a binary data serialization library and a distributed service registry. The platform distinguishes itself through a comprehensive governance suite that manages service discovery, load balancing, and traffic routing. It enables precise control over network traffic via conditional routing and a pluggable extension mechanism based on a ser

PikiwiDB is a distributed NoSQL database and disk-based key-value store that serves as a Redis-compatible protocol server. It is designed to handle datasets larger than available system memory by utilizing a persistence engine that stores the full dataset on disk. The system employs a tiered storage model, caching frequently accessed hot data in memory while maintaining the primary volume on disk. It ensures high availability through a replicated data store architecture, using asynchronous binary logs to synchronize data between primary and secondary nodes. The project supports distributed d

SpringBoot-Labs is a collection of educational resources and reference implementations for Java backend architecture and distributed systems. It provides practical lab guides and code samples focused on building applications with the Spring Boot framework and designing scalable microservices architectures. The project specifically covers service governance and distributed cloud deployment patterns using Spring Cloud and Spring Cloud Alibaba. It includes a dedicated kit for microservices and a guide for executing remote procedure calls and managing service discovery via the Dubbo protocol. Th

Vespa is a distributed search engine, vector database, and machine learning ranking engine. It serves as an AI search platform designed to handle large-scale document indexing and complex query processing across a cluster of nodes, combining keyword retrieval with high-dimensional embedding storage for semantic similarity search. The platform distinguishes itself by integrating machine learning models directly into the search pipeline to perform real-time inference and ranking. It converts these models into ranking expressions to score and order results based on relevance, while providing a s

This project is a comprehensive technical interview question bank and reference library designed for software engineering roles at major technology companies. It serves as a study guide and knowledge base covering the core principles of high-performance systems programming and computer science theory. The collection focuses on deep technical domains, including C++ language mastery, distributed systems design, and database engineering. It provides detailed material on consensus protocols, cluster coordination, and the architectural differences between SQL and NoSQL implementations. The resour

Akka.NET is an actor model framework used for building concurrent and distributed applications. It functions as a distributed computing platform and state manager that enables isolated actors to communicate via asynchronous message passing, ensuring thread-safe state management without manual locks. The project is distinguished by its decentralized coordination capabilities, including a distributed state manager that uses sharding and dynamic rebalancing to maintain high availability. It incorporates an event sourcing engine that persists state as a sequence of events in an append-only log an