What are the three important characteristics of object-oriented?

These three characteristics are encapsulation, inheritance and polymorphism.

Encapsulation refers to encapsulating the properties and behaviors of something into an object, and only the properties and behaviors that need to be disclosed can be selectively disclosed to other objects. In java, you can use or not use three modifiers, private, protected and public (that is, the default value) to restrict external objects from accessing the properties and behaviors of objects.

Inheritance means that a child object can inherit the properties and behaviors of the parent object, that is, the properties and behaviors of the parent object, and its child objects also have these properties and behaviors. This is very similar to the species inheritance in nature.

Polymorphism refers to allowing different kinds of objects to respond to the same message. For example, the same addition, adding two times together and adding two integers together must be completely different. For another example, the same selective editing and pasting operation has different effects in word processing programs and drawing programs. Polymorphism includes parameter polymorphism and inclusion polymorphism. Polymorphic language has the advantages of flexibility, abstraction, behavior enjoyment and code enjoyment, which well solves the problem of application functions with the same name.

Extended data:

Object-oriented (OO) is a software development method. The concept and application of object-oriented has gone beyond programming and software development, and extended to database system, interactive interface, application structure, application platform, distributed system, network management structure, CAD technology, artificial intelligence and other fields. Object-oriented is a method to understand and abstract the real world, which is the product of the development of computer programming technology to a certain stage.

When there are many problems in structured design methods, object-oriented came into being. The basic strategy of structured design method to solve problems is to examine the problem domain from the perspective of function. It regards the application as a functional module to realize some specific tasks, in which the sub-process is the bottom functional module to realize a specific operation. In each functional module, the data structure is used to describe the organizational form of data to be processed, and the algorithm is used to describe the specific operation process.

Reference Baidu Encyclopedia: Object-oriented