Jersey vs Lagom Framework: What are the differences?

# Introduction
This comparison discusses the key differences between Jersey and Lagom Framework.

1. **Architecture**: Jersey is a JAX-RS (Java API for RESTful web services) reference implementation that focuses on building RESTful web services using Java. On the other hand, Lagom Framework is a full-featured Microservices framework that provides not only RESTful APIs but also supports event sourcing and CQRS (Command Query Responsibility Segregation) patterns for building scalable and resilient systems.

2. **Scalability**: Jersey is primarily focused on building RESTful services in a stateless manner, which can limit its scalability when dealing with complex distributed systems. In contrast, Lagom Framework is built with scalability in mind, offering features like Akka actors and Kafka for building highly scalable and reactive systems.

3. **Service Discovery**: Jersey does not provide any built-in support for service discovery, leaving this responsibility to developers to handle using external tools or libraries. Lagom Framework, on the other hand, comes with integrated support for service discovery through its built-in service locator that allows services to automatically discover and communicate with each other.

4. **Persistence**: While Jersey does not provide any specific support for data persistence mechanisms, Lagom Framework offers persistence through its built-in support for event sourcing and CQRS. This allows developers to easily store and retrieve data in a scalable and fault-tolerant manner.

5. **Testing**: Jersey offers testing support through APIs like JUnit and Mockito, allowing developers to write unit tests for their RESTful services. Lagom Framework goes a step further by providing built-in support for integration testing of microservices, including features like embedded service testing and automatic test ports allocation.

6. **Polyglot Programming**: Jersey is primarily focused on Java development, limiting developers to build RESTful services using Java. In contrast, Lagom Framework allows developers to build microservices using multiple languages like Java and Scala, promoting polyglot programming and flexibility in technology choices.

In Summary, Jersey and Lagom Framework differ in architecture, scalability, service discovery, persistence, testing, and support for polyglot programming.