super in java

/* superclass Person */
class Person 
{ 
    Person(int i) 
    { 
        System.out.println("Person class Constructor"); 
    } 
} 
  
/* subclass Student extending the Person class */
class Student extends Person 
{ 
    Student() 
    { 
        // invoke or call parent class constructor 
        super(); 
  
        System.out.println("Student class Constructor"); 
    } 
} 
  
/* Driver program to test*/
class Test 
{ 
    public static void main(String[] args) 
    { 
        Student s = new Student(); 
    } 
} 

// Java code to demonstrate super() 
  
/* superclass Person */
class Person { 
    Person() 
    { 
        System.out.println("Person class Constructor"); 
    } 
} 
  
/* subclass Student extending the Person class */
class Student extends Person { 
    Student() 
    { 
        // invoke or call parent class constructor 
        super(); 
  
        System.out.println("Student class Constructor"); 
    } 
} 
  
/* Driver program to test*/
class Test { 
    public static void main(String[] args) 
    { 
        Student s = new Student(); 
    } 
} 

/* Base class Person */
class Person 
{ 
    void message() 
    { 
        System.out.println("This is person class"); 
    } 
} 
  
/* Subclass Student */
class Student extends Person 
{ 
    void message() 
    { 
        System.out.println("This is student class"); 
    } 
  
    // Note that display() is only in Student class 
    void display() 
    { 
        // will invoke or call current class message() method 
        message(); 
  
        // will invoke or call parent class message() method 
        super.message(); 
    } 
} 
  
/* Driver program to test */
class Test 
{ 
    public static void main(String args[]) 
    { 
        Student s = new Student(); 
  
        // calling display() of Student 
        s.display(); 
    } 
}