Java Inheritance Hierarchy: Subclasses, Parent Classes and Ancestors

Java inheritance is one of the core concepts of object-oriented programming, which builds the hierarchical structure between classes. In this structure, the subclass inherits the properties and methods of the parent class, and the parent class can inherit from the ancestor class. PHP editor Apple will introduce you to the hierarchical structure of Java inheritance in detail, including the relationship between subclasses, parent classes and ancestor classes, to help you better understand and apply the concept of inheritance.

inherit

Inheritance is an important concept in object-oriented programming that allows one class (subclass) to inherit properties and methods from another class (parent class). Subclasses inherit properties and methods from the parent class, but can also define their own specific properties and methods.

Class Hierarchy

Class hierarchy in Java follows the "is-a" relationship. A subclass is "a" form of its parent class. For example, a car class could inherit from a transportation tool class because a car is a form of transportation.

Subclass

A subclass is a class that inherits the attributes and methods of the parent class. Subclasses can extend or modify methods in the parent class, and can also define new methods of their own. The relationship between subclasses and parent classes is established through the extends keyword.

father

The parent class is the class from which the subclass inherits properties and methods. The parent class defines the basic properties and methods that subclasses can inherit. A parent class can have multiple subclasses, and each subclass can customize its properties and methods as needed.

ancestor

Ancestor is a relationship between a subclass and a parent class. An ancestor is a parent class or a higher-level parent class. In Java, any ancestor class can be traced since all classes ultimately inherit from the Object class.

Multi-level inheritance

Java supports multi-level inheritance, which means that a class can inherit properties and methods from multiple parent classes. This allows the creation of more complex and flexible class hierarchies.

Interface inheritance

The interface specifies the contract of the method, but does not provide implementation. A class can implement multiple interfaces and must provide implementations of all methods defined in the interfaces. Interface inheritance allows the creation of decoupled and reusable code.

advantage

Reusability: Inheritance allows the creation of reusable code because subclasses can inherit the properties and methods of the parent class.

• Extensibility: Inheritance enables subclasses to extend the functionality of the parent class and add their own methods as needed.
• Code Organization: Inheritance helps organize code because it allows shared properties and methods to be grouped into parent classes.

shortcoming

Code complexity: Multi-level inheritance may cause the code to become complex and difficult to maintain.

• Fragility: Changes to methods in the parent class may affect the child class, causing unexpected behavior.
• Redundancy: If multiple subclasses inherit the same properties or methods, it may lead to code redundancy.

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