The role of super keyword in java

The super keyword is an important keyword in the Java language. It has the following functions: 1. Call the parent class constructor; 2. Access the parent class members; 3. Obtain the proxy reference from the parent class; 4. Call the parent class method. Proper use of the super keyword is crucial to writing scalable and maintainable Java code.

The role of super keyword in Java

The super keyword is an important keyword in the Java language , used to access the methods and variables of the parent class in the subclass. It provides a variety of features to make Java programs more flexible and maintainable.

Function:

The super keyword mainly has the following functions:

• Call the parent class constructor: super The () statement appears in the first line of the subclass constructor and is used to call the parent class's constructor to initialize the parent class members.
• Accessing parent class members: Using the super. member name syntax, you can access variables and methods in the parent class, even if they have been overridden or hidden in the subclass.
• Get a proxy reference from the parent class: The super.getClass() statement returns the Class object of the parent class, allowing subclasses to access the parent class's methods and variables, even if they are private.
• Call the parent class method: super. The member method name (parameter) syntax can be used to explicitly call the parent class method without overriding it.

Usage examples:

The following are some examples showing the usage of the super keyword:

<code class="java">// 调用父类构造函数
public class Child extends Parent {
    public Child() {
        super(); // 调用 Parent 类的无参构造函数
    }

    public Child(int x) {
        super(x); // 调用 Parent 类的有参构造函数
    }
}

// 访问父类变量
public class Child extends Parent {
    @Override
    public String toString() {
        return "Child: " + super.name; // 访问父类中的 name 变量
    }
}

// 调用父类方法
public class Child extends Parent {
    @Override
    public void print() {
        super.print(); // 调用父类的 print() 方法
        System.out.println("Child"); // 添加子类自己的行为
    }
}</code>

Correct understanding and use of the super keyword for Writing scalable and maintainable Java code is crucial. It enables subclasses to take advantage of the functionality provided by the parent class while adding their own specific behavior.

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