Using comparable and comparator in java collection

	Comparable	Comparator
1	this interface allows the object to compare itself with another object while sorting the list of such type objects.	This interface provide the provision to compare two different objects.
2	The objects those implements Comparable interface are sorted automatically without specifying any other comparator.	Comparator is passed as arguments to the method who need to sort some objects.
3	less flexible	more flexible
4	uses compareTo(object2) method	it has compare(object1,object2) method
5	this interface is not a part of collection API. It belongs to java.lang Packages	this interface belongs to java.util package.

Using Comparable
package collection.examples;

import java.util.ArrayList;
import java.util.Collections;

class Contact implements Comparable<Contact>{
    String name;
    String email;
    int phone;
    public Contact(String name, String email, int phone) {
        this.name = name;
        this.email = email;
        this.phone = phone;
    }
    public int compareTo(Contact otherContact) {
        return this.name.compareTo(otherContact.name);
    }

    @Override
    public String toString() {
        return "Contact{" + "name=" + name + ", email=" + email + ", phone=" + phone + '}';
    }
}

 public class UsingComparable {
    public static void main(String[] args) {
        Contact c1=new Contact("rbc","mail1@gmail.com",2424342);
        Contact c2=new Contact("tbc","mail2@gmail.com",2424342);
        Contact c3=new Contact("bcc","mail3@gmail.com",2424342);
        ArrayList<Contact> al=new ArrayList<Contact>();
        al.add(c1);
        al.add(c2);
        al.add(c3);
        Collections.sort(al);
        for (Contact contact : al) {
            System.out.println(contact);
        }
    }
}

Using Comparator 
 package collection.examples;

import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;

class Contact1 {
    String name;
    String email;
    int phone;
    public Contact1(String name, String email, int phone) {
        this.name = name;
        this.email = email;
        this.phone = phone;
    }
 
    @Override
    public String toString() {
        return "Contact1{" + "name=" + name + ", email=" + email + ", phone=" + phone + '}';
    }
    
}
class MyComparator implements Comparator<Contact1>{

    public int compare(Contact1 o1, Contact1 o2) {
        //comparing name from both objects
        return o1.name.compareTo(o2.name);
    }   
}
public class UsingComparator {
    public static void main(String[] args) {
        Contact1 c1=new Contact1("zzz","mail1@gmail.com",2424342);
        Contact1 c2=new Contact1("bbb","mail2@gmail.com",2424342);
        Contact1 c3=new Contact1("ccc","mail3@gmail.com",2424342);
        ArrayList<Contact1> al=new ArrayList<Contact1>();
        al.add(c1);
        al.add(c2);
        al.add(c3);
        Collections.sort(al, new MyComparator());
        for (Contact1 contact : al) {
            System.out.println(contact);
        }
    }
}