How do components interact within a monolithic architecture?

In monolithic architecture, all components of the application are in a single process and are tightly coupled. Interaction occurs through direct function or method calls, without network protocols.

Main ways of component interaction within a monolith:

• Method/function calls: Components call each other directly, passing parameters and receiving results.
• Shared memory access: All components have access to shared data and objects in memory.
• Event handling: Sometimes, an event pattern is used to notify other components about changes.

For example, in a Java monolith, services may call repository methods to access data, and controllers may call service methods to handle business logic. All this happens within a single application and process, which simplifies communication but reduces scalability flexibility.