Explore the core knowledge and key skills of Java technology

Interpretation of core knowledge and key skills of Java technology

As a widely used programming language, Java has strong cross-platform, efficient performance and rich Function. Mastering the core knowledge and key skills of Java is crucial to improving programming capabilities and development efficiency. This article will introduce the core knowledge and key skills of Java technology in detail, and provide specific code examples to help readers better understand and apply.

1. Object-oriented programming (OOP)
Object-oriented programming is the core idea of ​​Java programming. It achieves more modularity, maintainability and reusability by encapsulating data and methods in objects. code. In Java, we use classes and objects to implement object-oriented programming.

The following is a simple Java class example:

public class Person {
    private String name;
    private int age;

    public Person(String name, int age) {
        this.name = name;
        this.age = age;
    }

    public void sayHello() {
        System.out.println("Hello, my name is " + name + " and I am " + age + " years old.");
    }
}

The above code defines a class named Person, which contains private name and age attributes and a public sayHello method. The constructor of the class is used to initialize the properties, and the sayHello method is used to output a greeting. The sample code for using this class to create an object is as follows:

public static void main(String[] args) {
    Person person = new Person("Alice", 25);
    person.sayHello();
}

Running the above code will output: Hello, my name is Alice and I am 25 years old. This is a simple object-oriented program.

2. Exception handling
Exceptions are errors or abnormal situations that may occur during program execution. Java provides an exception handling mechanism that allows developers to catch and handle exceptions when they occur, thereby ensuring the stability of the program.

The following is a simple Java exception handling example:

public static void divide(int a, int b) {
    try {
        int result = a / b;
        System.out.println("Result: " + result);
    } catch (ArithmeticException e) {
        System.out.println("Error: " + e.getMessage());
    }
}

public static void main(String[] args) {
    divide(10, 0);
}

The above code defines a divide method for division operations. Inside the divide method, we use a try-catch statement block to catch arithmetic exceptions that may occur (division by 0). If an arithmetic exception occurs, the code in the catch statement block will be executed and an error message will be output.

3. Multi-threaded programming
Multi-threaded programming is a powerful feature of Java. It allows the program to perform multiple tasks at the same time, improving the concurrency and responsiveness of the program. In Java, we can create threads by inheriting the Thread class or implementing the Runnable interface.

The following is a simple Java multi-threading example:

public class MyThread extends Thread {
    @Override
    public void run() {
        for(int i = 0; i < 10; i++) {
            System.out.println("Thread 1: " + i);
        }
    }
}

public static void main(String[] args) {
    MyThread thread1 = new MyThread();
    thread1.start();

    Thread thread2 = new Thread(new Runnable() {
        @Override
        public void run() {
            for(int i = 0; i < 10; i++) {
                System.out.println("Thread 2: " + i);
            }
        }
    });
    thread2.start();
}

The above code defines a MyThread class that inherits from the Thread class and overrides the run method. In the main method, we create two thread objects, start and execute their own run methods respectively. Running the above code will output the execution results of the two threads at the same time.

In fact, Java provides more multi-threaded programming tools, such as thread pools, locks, condition variables, etc., which can better control and manage threads.

This article only introduces some of the core knowledge and key skills of Java technology. Java is a very broad and in-depth programming language. There are many other knowledge and skills that require in-depth study and practice. I hope that readers will have a preliminary understanding of Java technology through the introduction of this article, and be able to apply these knowledge and skills in actual development.

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