What are the main methods of data exchange between system components?

Main ways of data exchange between system components in Java:

1. Method Calls – the simplest way, where one object calls methods of another, passing data through parameters and receiving results.

2. Event-driven communication – components exchange messages via events, for example, using listeners and handlers.

3. Shared Context or Singleton – data is stored in a common object or service accessible to multiple components.

4. Using Message Queues – for asynchronous data exchange between components, especially in distributed systems (e.g., JMS, RabbitMQ).

5. Through databases or cache – components write and read data from a shared database or cache.

6. REST API or other network protocols – data exchange between services via HTTP requests.

Example of a simple method call:

public class ComponentA {
    private ComponentB componentB;

    public ComponentA(ComponentB componentB) {
        this.componentB = componentB;
    }

    public void doWork() {
        String data = "Hello";
        componentB.processData(data);
    }
}

public class ComponentB {
    public void processData(String data) {
        System.out.println("Received: " + data);
    }
}