Refers to the communication rules between different functional layers of the same computer called interfaces.

Java interface functions:

1. Conducive to code standardization. On the one hand, the purpose of this is to give developers a clear instruction to tell them which businesses need to be implemented; at the same time, it can also prevent unclear naming and code confusion caused by developers' arbitrary naming, which affects development efficiency.

2. Conducive to code maintenance. You can define an interface at the beginning, put the function menu in the interface, and then implement this interface when defining a class. If you want to change it later, you will just refer to another class, so as to achieve the convenience of maintenance and expansion.

3. Ensure the security and tightness of the code. A good program must conform to the characteristics of high cohesion and low coupling, and can better realize the functions of the system without involving any specific implementation details. This is safer and more rigorous. This idea is generally more common in software development.