super (what does it mean in java

Super keyword is used in Java to refer to parent class members, including accessing parent class: Constructor: Call the parent class constructor to ensure that the parent class is initialized. Method: Call the method of the parent class and retain the behavior of the parent class in the subclass implementation. Fields: Access parent class fields with the same name, avoiding name conflicts and allowing access to original values.

The role of Super in Java

In Java, the super keyword is a reference to a parent class member Special keywords. It is mainly used in the following aspects:

1. Access the parent class constructor

Use super() in the subclass constructor to call the parent class's Constructor. This is the main step in constructing the child chain, ensuring that the initialization of the parent class is completed before the initialization of the child class.

Example:

<code class="java">class Parent {
    public Parent() {
        System.out.println("Parent constructor called");
    }
}

class Child extends Parent {
    public Child() {
        super(); // 调用父类构造函数
        System.out.println("Child constructor called");
    }
}</code>

2. Accessing parent class methods

If the subclass overrides the parent class method, Methods of the parent class can be called through the super keyword. This is useful for preserving parent class behavior in child class implementations.

Example:

<code class="java">class Parent {
    public void printMessage() {
        System.out.println("Parent printMessage");
    }
}

class Child extends Parent {
    @Override
    public void printMessage() {
        super.printMessage(); // 调用父类 printMessage
        System.out.println("Child printMessage");
    }
}</code>

3. Access parent class fields

If the subclass has a field with the same name as the parent class, you can Access parent class fields through the super keyword. This avoids name conflicts and allows access to the parent class's original value.

Example:

<code class="java">class Parent {
    public int age = 50;
}

class Child extends Parent {
    public int age = 25;

    public void printAge() {
        System.out.println("Child age: " + age);
        System.out.println("Parent age: " + super.age);
    }
}</code>

By using the super keyword, Java developers can access parent class constructors, methods, and fields, thereby promoting code readability, Maintainability and scalability.

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