sort compare

/*
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 */
package checkex;

import java.util.Collections;
import java.util.Comparator;
import java.util.List;

/**
 *
 * @author manju
 */
public class compareExample {
    public static void main(String[] args) {
        List<Person> persons = new java.util.ArrayList<Person>();
        persons.add(new Person("abc3", "def3", -10));
        persons.add(new Person("abc2", "def22", 32));
        persons.add(new Person("abc1", "def1", 65));
        persons.add(new Person("abc4", "def4", -10));
        persons.add(new Person("abc4", "def22", 10));
      
        System.out.println(persons);
        Collections.sort(persons, new Comparator<Person>() {

            @Override
            public int compare(Person t, Person t1) {
                //return t.getAge() - t1.getAge();
                        if(0 == t.getAge() || 0== t1.getAge() ){
            throw new NullPointerException();
        }else{
            int nameComparisonResult = t.getAge()-(t1.getAge());
            if(0 == nameComparisonResult){
                return t.getLname().compareTo(t1.getLname());
            }else{
                return nameComparisonResult;
            }
        }
            }
        });
        System.out.println(persons);

    }
  
}