In Java, static means "static" and is used to modify member variables and member methods. It can also form a static static code block or carry out static package import. The characteristics of static: 1. It is loaded as the class is loaded; 2. It exists before the object; 3. It is shared by all objects.
The operating environment of this tutorial: windows7 system, mysql8 version, Dell G3 computer.
Java is an object-oriented computer programming language. Java has the characteristics of simplicity, object-oriented, distributed, robustness, security, platform independence and portability, multi-threading, and dynamics. Now I will tell you what static means in Java.
static means "global" or "static" and is used to modify member variables and member methods. It can also form a static code block.
Characteristics of static:
1. Loaded as the class is loaded;
2. Prior to object existence;
3. Shared by all objects;
The role of static keyword in JAVA language
(1) Modify member variables
In java, static is most commonly used to modify the member functions and attributes of a class, making them become member functions and attributes of the class. This is relative to the object's methods and objects.
(2) Modified member methods
Modified member methods are also a type of modified member variables, because member methods also belong to member variables.
When a member function is declared as a static function, the function belongs to a function of the class, and this method can be called through class name.method name.
Avoids the tediousness and resource consumption of creating a new object through new in advance.
But at the same time, non-static member functions or member variables cannot be called in static-modified methods, because methods modified with static actually belong to the current class. If you now call a method of an object or a certain The member variables of the object, it will be a bit at a loss.
Methods declared as static have the following restrictions:
1. They can only call other static methods.
2· They can only access static data. · They cannot reference this or super in any way.
To call a static method is "class name. method name". The use of static methods is very simple as shown above. Generally speaking, static methods often provide some utilities for other classes in the application. A large number of static methods in Java class libraries are defined for this purpose. This method does not require the creation of objects.
(3) Static block
The characteristic of static block is that it is executed when the class is loaded and only executed once.
(4) Static import package
The static import package is the static import of the java package. Using import static instead of import static import package is a new feature in JDK1.5 .
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