super class in java code example

Example 1: how to make one java class inherit from another

public class Bicycle {
        
    // the Bicycle class has three fields
    public int cadence;
    public int gear;
    public int speed;
        
    // the Bicycle class has one constructor
    public Bicycle(int startCadence, int startSpeed, int startGear) {
        gear = startGear;
        cadence = startCadence;
        speed = startSpeed;
    }
        
    // the Bicycle class has four methods
    public void setCadence(int newValue) {
        cadence = newValue;
    }
        
    public void setGear(int newValue) {
        gear = newValue;
    }
        
    public void applyBrake(int decrement) {
        speed -= decrement;
    }
        
    public void speedUp(int increment) {
        speed += increment;
    }
        
}

Example 2: how to use super class method in java

class Parentclass
{
   //no-arg constructor
   Parentclass(){
	System.out.println("no-arg constructor of parent class");
   }
   //arg or parameterized constructor
   Parentclass(String str){
	System.out.println("parameterized constructor of parent class");
   }
}
class Subclass extends Parentclass
{
   Subclass(){
       /* super() must be added to the first statement of constructor 
	* otherwise you will get a compilation error. Another important 
	* point to note is that when we explicitly use super in constructor
	* the compiler doesn't invoke the parent constructor automatically.
	*/
	super("Hahaha");
	System.out.println("Constructor of child class");

   }
   void display(){
	System.out.println("Hello");
   }
   public static void main(String args[]){		
	Subclass obj= new Subclass();
	obj.display();	 
   }
}