Java Basics Learning Notes (i)

Understanding Object-oriented:

Java's purely object-oriented programming language mainly shows that Java fully supports the three basic features of object-oriented: inheritance, encapsulation, polymorphism.

The smallest unit of a Java program is a class , which represents a kind of thing with a certain characteristic in the objective world, which can generate multiple objects in the system, and these objects directly map to the various things in the objective world, and the whole Java program consists of one class.

Structured (pro-functional)/object-oriented Programming: (Analysis > Design > Programming) SA/OOA > Sd/ood > Sp/oop

The minimal program unit is a function , each function is responsible for the completion of a function, the whole program is composed of a function, which as the function of the entrance of the program becomes the main function, the main function calls other functions in turn to complete the function of the whole software system.

Any simple or complex algorithm can be composed of three basic structures: sequence, selection, and loop structure.

UML Unified Modeling Language: is a language used to visually model software-intensive systems.

UML describes, visualizes, and compiles products for object-oriented development systems.
A standard language for documents.

The goal of UML is to describe an object-oriented graph in which any type of system has a wide
field of use. One of the most common is the model of a software system, but it can also be used to describe non-software
Systems, such as mechanical systems, corporate institutions or business processes, and the information system that handles complex data
Industrial systems or industrial processes with real-time requirements. In short, UML is a common standard built
Model language, which can be modeled on any system that has a static structure and dynamic behavior.

UML is suitable for the system development process from the requirements specification to the system after the completion of testing
The same stage. Use cases can be used to capture user requirements during the requirements analysis phase. Modeling with Use cases: description
External roles that are of interest to the system and their functional requirements for systems (use cases). The main concern in the analysis phase
Concepts (such as abstractions, classes, objects, and so on) and mechanisms that need to identify these classes and
Relationships and are described using UML class diagrams. To achieve collaboration between the use case classes, this can be
UML dynamic model to describe. In the analysis phase, only the object of the problem domain (the real-world concept) is modeled,
Classes that define technical details in a software system, such as handling user interfaces, databases, communications, and parallel
Problems such as sex). These technical details are introduced in the design phase, so the design phase
For a more detailed description of the specification.

Java Basics Learning Notes (i)