In object-oriented programming, how do objects communicate with each other?

In object-oriented programming, objects communicate with each other primarily by passing messages. This communication occurs through method calls, where one object sends a request to another object to perform a specific action or to retrieve data. The concept of message passing is foundational in object-oriented design, as it allows different objects to interact with each other while encapsulating their internal state and behavior.

When one object needs to collaborate with another, it sends a message that typically consists of a method name and parameters, if necessary. The receiving object then executes the corresponding method and may return a result back to the original sender. This structure supports modularity and code reuse, allowing for easier maintenance and enhancement of software systems.

While variables hold data, classes define the blueprint for objects, and inheritance allows for the creation of subclasses from a base class, these concepts do not directly describe the mechanism of inter-object communication in the same way that message passing does. Message passing emphasizes the dynamic interaction between objects, which is a core principle in achieving effective object-oriented programming.