Expected Understanding: Interface, access modifiers, Method Overriding
1) Create a package called tamilnadu.chennai
2) Create an interface ‘TrafficRules’ under this package
3) Make sure this interface is public interface
– Add variable String trafficCommisssioner = “Kavin”;
– Add below methods
– void goByDieselVehicle();
– void goByBicycle();
package tamilnadu.chennai;
public interface TrafficRules
{
String trafficCommissioner = "Kavin";
public void goByDieselVehicle();
public void goByBicycle();
}4) Create class called ‘CommonManInChennai’ with main method in the same package tamilnadu.chennai
– Implement interface ‘TrafficRulesChennai’
– Create instance for this class and access all the methods
package tamilnadu.chennai;
public class CommonManinChennai implements TrafficRules
{
public static void main(String[] args)
{
CommonManinChennai cm = new CommonManinChennai();
cm.goByDieselVehicle();
cm.goByBicycle();
}
public void goByDieselVehicle()
{
System.out.println("Car");
}
public void goByBicycle()
{
System.out.println("Cycling");
}
}5) Now, create another package called ‘india.newDelhi’
6) Create an interface ‘TrafficRulesDelhi’ under this package
7) Make sure this interface is not public interface – it should be default interface
– Add variable String trafficCommisssioner = “Navin”;
– Add below methods
– void dontGoByDieselVehicle();
– void goByBicycle();
package india.newDelhi;
interface TrafficRulesDelhi
{
String trafficCommissioner = "Naveen";
public void dontGoByDieselVehicle();
public void goByBicycle();
}8) Create class called ‘CommonManInDelhi’ with main method in the same package india.newDelhi
– Implement interface ‘TrafficRulesDelhi’
– Create instance for this class and access all the methods
– Now, implement interface ‘TrafficRulesChennai’ also.
– Add unimplemented methods
– Access all the methods and observe the difference.
package india.newDelhi;
import tamilnadu.chennai.TrafficRules;
class CommonManinDelhi implements TrafficRulesDelhi,TrafficRules
{
public static void main(String[] args)
{
CommonManinDelhi cd = new CommonManinDelhi();
cd.dontGoByDieselVehicle();
cd.goByBicycle();
}
public void dontGoByDieselVehicle()
{
System.out.println("Don't Go");
}
public void goByBicycle()
{
System.out.println("Go");
}
public void goByDieselVehicle()
{
System.out.println("Go by vehicle");
}
/* public void goByBicycle() // method already declared
{
System.out.println("Go by bicycle");
}*/
}Output
After the Error (GoByBicycle() method already declared so remove that method)
