Extending classes inheritance and Accessibility
Extending classes inheritance and Accessibility
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This program shows how the classes are extending .means how sub class extending from the super class.
Inheritance allows new classes to be derived from an existing class.
In java implementation inheritance is achieved by extending classes and modified inherited members.
adding new fields and methods.
In this program Light is a Class .
indicator ,location and counter are its fields.
Tubelight is a sub class which is extend from the Class Light .it has its own fields. it inherit the methods of class Light
package Example;
public class Light {
//instance fields
int noOfWatts; //wattage
private boolean indicator; //on or off
protected String location; //placement
//Static fields
private static int counter ; //no.of light objects created
//Constructor
Light(){
noOfWatts = 50;
indicator = true;
location = "x";
counter++;
}
//Instance methods
public void switchOn(){indicator = true;}
public void switchOn(){indicator = false;}
public boolean isOn(){return indicator ;}
private void printLocation(){
System.out.println("Location:" + counter);
}
}
class TubeLight extends Light{ // subclass uses the extends clause.
//instance fields
private int tubeLength = 54;
private int colorNo = 10;
//instance methods
public int getTubeLength(){return tubeLength;}
public void printInfo(){
System.out.println("Tube length :" +getTubeLength());
System.out.println("Color number:"+ colorNo);
System.out.println("Wattage :" + noOfWatts);//inherited
System.out.println("Indicator:" + indicator );//not inherited
System.out.println("Indictor:" + isOn()); //inherited
System.out.println(" Location : "+ location);//inherited
//print Location();
//System.out.println("Counter :" +counter ); //not inherited
writeCount();
}
}
public class Utility{
/**
* @param args
*/
public static void main(String[] args) {
new TubeLight().printInfo();
// TODO Auto-generated method stub
}
}
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