Reveal the secrets of Java encapsulation and inheritance, and build a path to clear code

• Definition: Encapsulation refers to hiding the implementation details of the properties and methods of an object and only exposing the necessary interfaces.
• effect:
  • Improve the maintainability and reusability of the code, because the internal implementation can be changed at any time without affecting external use.
  • Enhance Security because it limits access to sensitive data.

Java is a very popular programming language, but if you want to be an excellent Java programmer, you not only need to be familiar with the Java language itself, but also need to understand important concepts and usage methods such as Java encapsulation, inheritance, and polymorphism. PHP editor Youzi will reveal the secrets of Java encapsulation and inheritance, and build a clear and easy-to-understand Java code path for everyone. In this process, everyone can master Java's core syntax and object-oriented programming ideas through practice, thereby better understanding the Java programming process and improving their programming skills.

• Definition: Inheritance allows one class (subclass) to inherit data members and methods from another class (parent class).
• effect:
  • Code reusability: Subclasses can reuse the code of the parent class to avoid repeated writing.
  • Polymorphism: Subclasses can override the methods of the parent class to achieve different behaviors.

Interaction of encapsulation and inheritance

• Private methods: Private methods can only be accessed within the class. They hide specific implementation details and improve encapsulation.
• Protected methods: Protected methods can be accessed by subclasses, but cannot be accessed by other classes. This provides more flexible visibility control than private while still maintaining encapsulation.
• Public methods: Public methods can be accessed by any class. They are usually interfaces for external interaction.

Best Practices for Building Clean Code

• Follow SOLID principles: Encapsulation (S) and inheritance (I) are an integral part of the SOLID principles. By following these principles, you can write code that is clear, maintainable, and reusable.
• Use appropriate visibility levels: Carefully consider the visibility level of each method and property to maintain appropriate encapsulation and flexibility.
• Avoid excessive inheritance: Inheritance should be used with caution because it can introduce coupling and complexity. Use inheritance only if it makes logical sense.
• Using polymorphism: Polymorphism allows subclasses to be referenced and used with the parent class type. This promotes loose coupling and scalability.
• Testing and Refactoring: Regularly Test your code and refactor it to maintain its clarity and efficiency.

Example:

// 父类 Animal
public class Animal {
private String name; // 私有属性
protected void move() { // 受保护方法
System.out.println("动物在移动");
}
public void speak() { // 公共方法
System.out.println("动物在叫");
}
}

// 子类 Dog
public class Dog extends Animal {
@Override
public void move() { // 方法重写
System.out.println("狗在跑");
}
public void bark() { // 子类独有方法
System.out.println("狗在吠叫");
}
}

In this example, the Animal class encapsulates the implementation of properties and methods, providing a clear interface. The Dog class inherits the move() method from Animal and overrides it, demonstrating polymorphism.

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