apache/dubbo

Apache Dubbo is an open-source Java framework for building distributed microservices applications. Originally created at Alibaba and later donated to the Apache Software Foundation, it solves the problem of how separate services in a large application talk to each other reliably and efficiently across a network. In a microservices architecture, you might have dozens or hundreds of individual services, a user service, an order service, a payment service, and so on, each running on different servers. When one service needs to call a function in another, it cannot just call a method directly the way it would in a single program. Instead, it has to make a network call, handle failures, figure out which server is available, spread the load across multiple instances, and ensure calls are fast. This is called RPC (Remote Procedure Call), and Dubbo handles all of this complexity. Here is how it works: a service provider defines a Java interface and registers itself with a service registry (typically Apache ZooKeeper or Nacos, centralized directories that track which services are running and where). A consumer wanting to call that service looks up the registry to find available providers, then Dubbo makes the actual network call transparently. From the consumer's perspective, it looks like a normal Java method call. Dubbo handles serialization (converting objects to bytes for transmission), load balancing (distributing calls across multiple provider instances), automatic retry on failure, circuit breaking (stopping calls to unhealthy services), and traffic routing rules. Dubbo supports multiple protocols including its own high-performance binary protocol, gRPC, HTTP/2, and REST. You would use Dubbo when building large-scale Java backend systems where different services need to communicate efficiently, it is particularly prevalent in Chinese enterprise applications and large e-commerce platforms. The stack is Java, with Spring Boot integration and support for service registries like ZooKeeper, Nacos, or Consul.