Detailed introduction to Java keyword static
static means "global" or "static", is used to modify members variables With member methods, static code blocks can also be formed, but There is no concept of global variables in the Java language.
Member variables and member methods modified by static are independent of any objects of the class. That is, it does not depend on a specific instance of the class and is shared by all instances of the class. As long as this class is loaded,
The Java virtual machine can determine the method area in the runtime data area based on the class name. Find them. Therefore, a static object can be accessed before any of its objects are created, without referencing any objects.
The static member variables and member methods modified with public are essentially global variables and global methods. When an object of its class is declared, a copy of the static variable is not generated, but All instances of a class share the same static variable.
static variable can be preceded by private modification, indicating that this variable can be used in the static code block of the class, or in other static member methods of the class (of course it can also be used in non-static member methods used in --- nonsense), but it is important not to directly reference it through the class name in other classes. In fact, you need to understand that private means access permission restriction, and static means it can be used without instantiation, which is much easier to understand. The effect of adding other access rights keywords in front of static is also the same.
Some characteristics of static:
(1) Static variables are also called static The difference between variables, static variables and non-static variables is that static variables are shared by all objects and have only one copy in memory. It will be initialized when and only when the class is first loaded. Non-static variables are owned by the object and are initialized when creating the object. There are multiple copies, and the copies owned by each object do not affect each other.
(2) statice has two functions: first, it only wants to allocate a single storage space for a specific domain, regardless of how many objects are created, or even no objects are created; second, , hope that a method is not associated with any object containing it, that is, any method in it can be called without creating any object.
(3) Any member variables and member methods modified by statice are independent of any object of the class. It does not depend on any object of the class and is shared by all instances.
(4) Static variables have only one copy in the memory. JVM only allocates static memory once. The memory allocation for static variables is completed during the process of loading the class. You can use the class name to directly access.
(5) Static code is bound to class. Successful loading of class means your static code has been executed and you will not do this again in the future. Static code. The function of Class.forName() is to ask the JVM to find and load the specified class, which means that the JVM will execute the static code segment of the class.
(6) Static method Attribute initialization is initialized when the class is loaded. Instead of static method property initialization.
Example:
public class Test {
static int i;
static
{
i++;
System.out.println("outt i:"+i);
}
static void outi()
{
i++;
System.out.println("output i:"+i);
}
public static void main(String [] argStrings)
{
Test test=new Test();
test.outi();
}
}##Output result:
outt i:1 output i:2
##
The above is the detailed content of Detailed introduction to Java keyword static. For more information, please follow other related articles on the PHP Chinese website!
Hot AI Tools
Undresser.AI Undress
AI-powered app for creating realistic nude photos
AI Clothes Remover
Online AI tool for removing clothes from photos.
Undress AI Tool
Undress images for free
Clothoff.io
AI clothes remover
Video Face Swap
Swap faces in any video effortlessly with our completely free AI face swap tool!
Hot Article
Hot Tools
Notepad++7.3.1
Easy-to-use and free code editor
SublimeText3 Chinese version
Chinese version, very easy to use
Zend Studio 13.0.1
Powerful PHP integrated development environment
Dreamweaver CS6
Visual web development tools
SublimeText3 Mac version
God-level code editing software (SublimeText3)
Hot Topics
Break or return from Java 8 stream forEach?
Feb 07, 2025 pm 12:09 PM
Java 8 introduces the Stream API, providing a powerful and expressive way to process data collections. However, a common question when using Stream is: How to break or return from a forEach operation? Traditional loops allow for early interruption or return, but Stream's forEach method does not directly support this method. This article will explain the reasons and explore alternative methods for implementing premature termination in Stream processing systems. Further reading: Java Stream API improvements Understand Stream forEach The forEach method is a terminal operation that performs one operation on each element in the Stream. Its design intention is
PHP: A Key Language for Web Development
Apr 13, 2025 am 12:08 AM
PHP is a scripting language widely used on the server side, especially suitable for web development. 1.PHP can embed HTML, process HTTP requests and responses, and supports a variety of databases. 2.PHP is used to generate dynamic web content, process form data, access databases, etc., with strong community support and open source resources. 3. PHP is an interpreted language, and the execution process includes lexical analysis, grammatical analysis, compilation and execution. 4.PHP can be combined with MySQL for advanced applications such as user registration systems. 5. When debugging PHP, you can use functions such as error_reporting() and var_dump(). 6. Optimize PHP code to use caching mechanisms, optimize database queries and use built-in functions. 7
PHP vs. Python: Understanding the Differences
Apr 11, 2025 am 12:15 AM
PHP and Python each have their own advantages, and the choice should be based on project requirements. 1.PHP is suitable for web development, with simple syntax and high execution efficiency. 2. Python is suitable for data science and machine learning, with concise syntax and rich libraries.
PHP vs. Other Languages: A Comparison
Apr 13, 2025 am 12:19 AM
PHP is suitable for web development, especially in rapid development and processing dynamic content, but is not good at data science and enterprise-level applications. Compared with Python, PHP has more advantages in web development, but is not as good as Python in the field of data science; compared with Java, PHP performs worse in enterprise-level applications, but is more flexible in web development; compared with JavaScript, PHP is more concise in back-end development, but is not as good as JavaScript in front-end development.
PHP vs. Python: Core Features and Functionality
Apr 13, 2025 am 12:16 AM
PHP and Python each have their own advantages and are suitable for different scenarios. 1.PHP is suitable for web development and provides built-in web servers and rich function libraries. 2. Python is suitable for data science and machine learning, with concise syntax and a powerful standard library. When choosing, it should be decided based on project requirements.
Java Program to Find the Volume of Capsule
Feb 07, 2025 am 11:37 AM
Capsules are three-dimensional geometric figures, composed of a cylinder and a hemisphere at both ends. The volume of the capsule can be calculated by adding the volume of the cylinder and the volume of the hemisphere at both ends. This tutorial will discuss how to calculate the volume of a given capsule in Java using different methods. Capsule volume formula The formula for capsule volume is as follows: Capsule volume = Cylindrical volume Volume Two hemisphere volume in, r: The radius of the hemisphere. h: The height of the cylinder (excluding the hemisphere). Example 1 enter Radius = 5 units Height = 10 units Output Volume = 1570.8 cubic units explain Calculate volume using formula: Volume = π × r2 × h (4
PHP: The Foundation of Many Websites
Apr 13, 2025 am 12:07 AM
The reasons why PHP is the preferred technology stack for many websites include its ease of use, strong community support, and widespread use. 1) Easy to learn and use, suitable for beginners. 2) Have a huge developer community and rich resources. 3) Widely used in WordPress, Drupal and other platforms. 4) Integrate tightly with web servers to simplify development deployment.
Create the Future: Java Programming for Absolute Beginners
Oct 13, 2024 pm 01:32 PM
Java is a popular programming language that can be learned by both beginners and experienced developers. This tutorial starts with basic concepts and progresses through advanced topics. After installing the Java Development Kit, you can practice programming by creating a simple "Hello, World!" program. After you understand the code, use the command prompt to compile and run the program, and "Hello, World!" will be output on the console. Learning Java starts your programming journey, and as your mastery deepens, you can create more complex applications.
