What is tight coupling? What are its disadvantages? And what are the disadvantages of too weak coupling?.

Strong coupling — this is a situation where system components are highly dependent on each other, for example, one class directly uses the internal details of another. Disadvantages of strong coupling:

• Difficulty in making changes: modifications in one component require adjustments in related ones.
• Testing difficulties: it is hard to isolate components for unit tests.
• Poor scalability and maintainability of the code.

On the other hand, too weak coupling (too high level of abstraction and separation) can also be problematic:

• Architecture complication: many unnecessary interfaces and abstractions.
• Reduced performance due to additional call levels.
• Difficulties in understanding the code due to excessive complexity.

The optimal approach is to maintain moderate coupling, where components are sufficiently independent for flexibility and testability, but not overly fragmented.