java修饰符学习（Java modifier learning）.docVIP

java修饰符学习（Java modifier learning） Object oriented technology has become the dominant technology in software development, and in the process, it almost changes every aspect of computer science. Several concepts: Class: collection of objects, object templates. For example: the reality of the car is a class, it has the cars common properties and behavior: such as power driven, there are four or more than four wheels, refueling, etc.. Cars, vans, trucks, etc. are all their subclasses. They all have the attributes and behavior of the car (its parent). (Note: subclasses are also classes, and they may have subclasses). Thats inheritance. Java supports single inheritance only, that is, a class can only have one parent class. Objects are classes that are specific: a class can have more than one object. A class can have multiple subclasses, each of which is not the same. The saying goes: a mother gives birth to nine children, and nine children are different.. For example, the car can be a four wheel drive or a two wheel drive, etc. Santana 3000 has red, white, black and other colors (this is polymorphism of the class). We can use Santana 3000, but we dont know how it was made. This hides the details of the implementation of the user and encapsulates it. Class encapsulation, inheritance and polymorphism are three core features of object oriented programming. Package: an efficient mechanism for managing classes that actually correspond to a series of folders, which are similar to the usual management files. Class name requirements: 1, can not use keywords; 2, the first character can not be the number; 3, the first letter should be capitalized, with the package can not be repeated; 4, the class name should be meaningful. My first example was so good that I didnt follow the fourth. The modifier problem, is blocking a stone in front of the Java for beginners. Whether its a class, a method, or a variable, we always remember, forget, forget. Do not grasp the use of modifiers, there