Java Program Using Pre Defined Interface Concept

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Aim:

To write a java program using pre defined interface concept.

Algorithm:

  1. Create a class called person which implements predefined interface comparable
  2. Declare data members name and lastname in a constructor.
  3. Define the member function getName() and getLastName()
  4. CompareTo () is the method of comparable interface
  5. Create a List object called mylist in order to store the objects.
  6. Sort the lists by using sort ()
  7. Display the sorted list.

INTERFACES-DEVELOPING PRE DEFINED INTERFACES

Program:

import java.util.ArrayList;   
import java.util.Collections;
class Person implements Comparable<Person>
{
private String firstname;
private String lastname;
Person(String a,String b)
{
this.firstname=a;
this.lastname=b;
}
public int compareTo(Person n)
{
return this.firstname.compareTo(n.firstname);
}
String getFirstName()
{
return this.firstname;
}
String getLastName()
{
return this.lastname;
}
}
public class Main
{
public static void main(String[] args) {
ArrayList<Person> al=new ArrayList<Person>(); 	
al.add(new Person("AAA","BBB"));  
al.add(new Person("CCC","DDD"));
al.add(new Person("EEE","FFF"));
al.add(new Person("GGG","HHH"));
al.add(new Person("III","JJJ"));
Collections.sort(al);  
for(Person str:al){  
System.out.println(str.getFirstName()+" "+
str.getLastName());  
} 
}
}

Execution:

AAA BBB
CCC DDD
EEE FFF
GGG HHH
III JJJ

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