What is the role of interface in java

Interfaces in Java define a set of method signatures but do not provide implementations. They are used to: 1. Define contracts to ensure consistent interaction between different classes; 2. Decouple abstraction and implementation; 3. Promote polymorphism; 4. Isolate changes. Application scenarios include: service contract, data abstraction, event processing, strategy pattern and dependency injection.

The role of interfaces in Java

The interface is a mechanism for defining contracts in Java. It defines A set of method signatures without providing an implementation. Interfaces are used to:

Define contracts:
Interfaces force objects that implement them to implement defined methods. This ensures that different classes interact with each other in a consistent manner.

Decoupling abstraction and implementation:
Interfaces separate abstraction and implementation. This allows developers to focus on the abstract aspects of the interface without worrying about the underlying implementation.

Promote polymorphism:
Interfaces allow objects to interact in a polymorphic manner. This means that objects that implement different interfaces can be treated as the same type, making it easy to write generic code.

Isolate changes:
Interfaces provide a way to change implementations without affecting client code. When the implementation needs to be modified, only the implementation class needs to be modified, without modifying the interface.

Application scenarios:

Interfaces are widely used in the following scenarios in Java applications:

• Service contract: Define the interaction between service providers and consumers.
• Data abstraction: Define data models and operations without exposing the underlying implementation.
• Event handling: Define the event listener interface to allow objects to subscribe to events.
• Strategy Mode: Define a family of algorithms so that clients can choose different strategies at runtime.
• Dependency Injection: Define dependency contracts so that objects can obtain dependencies without hard-coding implementation classes.

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