Can a subclass have multiple parent classes in Java?

Answer: No, in Java, a class can only have one direct parent class. Details: Java uses a single inheritance model, which means that a child class can inherit properties and methods from only one parent class. Single inheritance is to avoid the diamond inheritance problem, that is, a subclass inherits from two parent classes at the same time, resulting in method coverage and ambiguity problems. The alternative is to implement multiple inheritance through interfaces, where subclasses can implement multiple interfaces to inherit functionality from multiple parent classes.

Can a subclass in Java have multiple parent classes?

Answer: No

In Java, a class can only have one direct parent class, which is the so-called "single inheritance". This means that a subclass can only inherit properties and methods from one parent class.

Reason:

Java uses single inheritance to avoid the diamond inheritance problem. Diamond inheritance refers to the problem that when a subclass inherits from two parent classes at the same time, the resulting inheritance relationship graph forms a diamond shape. This can lead to problems with method coverage and ambiguity.

Alternatives:

Although Java does not support multiple inheritance, there are other languages ​​that provide similar multiple inheritance functionality through interfaces. An interface can define methods and variables, but cannot contain their implementation. A class can implement multiple interfaces to achieve similar multiple inheritance behavior.

Example:

// 定义接口
interface Animal {
    void eat();
}

interface Canine {
    void bark();
}

// 定义子类
class Dog implements Animal, Canine {
    @Override
    public void eat() {
        // 实现 eat 方法
    }

    @Override
    public void bark() {
        // 实现 bark 方法
    }
}

In this example, the Dog class implements Animal and Canine The interface has the function of inheriting properties and methods from two parent classes at the same time.

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