List Iterator:
==============
-> Can able to make the iteration on the list of objects in both forward and backward direction.

/*
 * WAP in Java to create the ArrayList to store Employee Object.
 * And Display the information of Female Employees only.
 * And also display the employee information who are having above 5 years of experience.
 */

package pack1;

import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.ListIterator;

class Employee{
	private int empNo;
	private String ename;
	private double salary;
	private String gender;
	private double experience;
	
	// creating the constructor for initializing class data members
	
	public Employee(int empNo, String ename, double salary, String gender, double experience) {
		super();
		this.empNo = empNo;
		this.ename = ename;
		this.salary = salary;
		this.gender = gender;
		this.experience = experience;
	}
	
	// defining setters and getters

	public int getEmpNo() {
		return empNo;
	}

	public void setEmpNo(int empNo) {
		this.empNo = empNo;
	}

	public String getEname() {
		return ename;
	}

	public void setEname(String ename) {
		this.ename = ename;
	}

	public double getSalary() {
		return salary;
	}

	public void setSalary(double salary) {
		this.salary = salary;
	}

	public String getGender() {
		return gender;
	}

	public void setGender(String gender) {
		this.gender = gender;
	}

	public double getExperience() {
		return experience;
	}

	public void setExperience(double experience) {
		this.experience = experience;
	}
	
	// generate toString()

	@Override
	public String toString() {
		return "Employee [empNo=" + empNo + ", ename=" + ename + ", salary=" + salary + ", gender=" + gender
				+ ", experience=" + experience + "]";
	}
	
	
	
}

public class MainClass {
	
	private static  ArrayList<Employee> getEmployeeList(){
		ArrayList<Employee> empList = new ArrayList<>();
		empList.add(new Employee(7928,"Amisha",55000.0,"Female",3.5));
		empList.add(new Employee(7929,"Ashok",45000.0,"Male",3.2));
		empList.add(new Employee(7930,"Akshay",25000.0,"Male",1.5));
		empList.add(new Employee(7931,"Bhavana",76000.0,"Female",5.5));
		empList.add(new Employee(7932,"Keerthi",45000.0,"Female",3.0));
		empList.add(new Employee(7933,"Vijay Gopal",105000.0,"Male",6.5));
		empList.add(new Employee(7934,"Vijay",35000.0,"Male",1.5));
		empList.add(new Employee(7935,"Vinitha",45000.0,"Female",3.0));
		empList.add(new Employee(7936,"Vignesh",125000.0,"Male",6.7));
		empList.add(new Employee(7937,"Ananya",119000.0,"Female",7.1));
		
		return empList;
	}

	public static void main(String[] args) {
		List<Employee> empList = getEmployeeList();
		
		ListIterator<Employee> litr = empList.listIterator();
		
		// Traversing on Employee List in forward Direction
		while(litr.hasNext()) {
			litr.next();
		}
		
		// Traversing on Employee List in reverse direction
		
		while(litr.hasPrevious()) {
			System.out.println(litr.previous());
		}
	}
}
=======================================================================
Sorting:
========
sort():
=======
-> this can use to perform the sorting on the collections.
-> sort() is the method of Collections.
Syntax:
	Collections.sort();

comparable<T> Interface:
=========================
-> Types of interfaces:
	3-types:
		1) Normal Interface ==> define with more than one abstract methods
		2) Marker Interface ==> define with 0 abstract methods
		3) Functional Interface ==> define with Single Abstract Method
			also called as "sam interface"
-> comparable interface is the type of functional interface because it has single abstract method (sam) called as "compareTo()".
-> To perform the natural sorting (Ascending order), the class should be implements from comparable interface.
Syntax:
	class Student implements comparable<Student>{
		// variables;
		// constructor;
		// setters/getters
		@Override
		public int compareTo(Student o){
			// logic;
		}
	}

package package1;

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


class Employee implements Comparable<Employee>{
	private int empNo;
	private String ename;
	private double salary;
	private String gender;
	private double experience;
	
	// creating the constructor for initializing class data members
	
	public Employee(int empNo, String ename, double salary, String gender, double experience) {
		super();
		this.empNo = empNo;
		this.ename = ename;
		this.salary = salary;
		this.gender = gender;
		this.experience = experience;
	}
	
	// defining setters and getters

	public int getEmpNo() {
		return empNo;
	}

	public void setEmpNo(int empNo) {
		this.empNo = empNo;
	}

	public String getEname() {
		return ename;
	}

	public void setEname(String ename) {
		this.ename = ename;
	}

	public double getSalary() {
		return salary;
	}

	public void setSalary(double salary) {
		this.salary = salary;
	}

	public String getGender() {
		return gender;
	}

	public void setGender(String gender) {
		this.gender = gender;
	}

	public double getExperience() {
		return experience;
	}

	public void setExperience(double experience) {
		this.experience = experience;
	}
	
	// generate toString()

	@Override
	public String toString() {
		return "Employee [empNo=" + empNo + ", ename=" + ename + ", salary=" + salary + ", gender=" + gender
				+ ", experience=" + experience + "]";
	}
	
	@Override
	public int compareTo(Employee o) {
		return this.getEmpNo()-o.getEmpNo();
	}
	
}

public class MainClass {
	
	private static  ArrayList<Employee> getEmployeeList(){
		ArrayList<Employee> empList = new ArrayList<>();
		empList.add(new Employee(7928,"Amisha",55000.0,"Female",3.5));
		empList.add(new Employee(8029,"Ashok",45000.0,"Male",3.2));
		empList.add(new Employee(7930,"Akshay",25000.0,"Male",1.5));
		empList.add(new Employee(7731,"Bhavana",76000.0,"Female",5.5));
		empList.add(new Employee(9732,"Keerthi",45000.0,"Female",3.0));
		empList.add(new Employee(9833,"Vijay Gopal",105000.0,"Male",6.5));
		empList.add(new Employee(8034,"Vijay",35000.0,"Male",1.5));
		empList.add(new Employee(7635,"Vinitha",45000.0,"Female",3.0));
		empList.add(new Employee(6736,"Vignesh",125000.0,"Male",6.7));
		empList.add(new Employee(7937,"Ananya",119000.0,"Female",7.1));
		
		return empList;
	}

	public static void main(String[] args) {
		List<Employee> lstEmp = getEmployeeList();
		Collections.sort(lstEmp);
		
		// for each loop
		System.out.println("The Employee after the sorting based on the Employee ID = ");
		for(Employee e:lstEmp) {
			System.out.println(e);
		}
	}

}

======================================
If you want to do the sorting based on the employee name:
==========================================================
package package1;

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


class Employee implements Comparable<Employee>{
	private int empNo;
	private String ename;
	private double salary;
	private String gender;
	private double experience;
	
	// creating the constructor for initializing class data members
	
	public Employee(int empNo, String ename, double salary, String gender, double experience) {
		super();
		this.empNo = empNo;
		this.ename = ename;
		this.salary = salary;
		this.gender = gender;
		this.experience = experience;
	}
	
	// defining setters and getters

	public int getEmpNo() {
		return empNo;
	}

	public void setEmpNo(int empNo) {
		this.empNo = empNo;
	}

	public String getEname() {
		return ename;
	}

	public void setEname(String ename) {
		this.ename = ename;
	}

	public double getSalary() {
		return salary;
	}

	public void setSalary(double salary) {
		this.salary = salary;
	}

	public String getGender() {
		return gender;
	}

	public void setGender(String gender) {
		this.gender = gender;
	}

	public double getExperience() {
		return experience;
	}

	public void setExperience(double experience) {
		this.experience = experience;
	}
	
	// generate toString()

	@Override
	public String toString() {
		return "Employee [empNo=" + empNo + ", ename=" + ename + ", salary=" + salary + ", gender=" + gender
				+ ", experience=" + experience + "]";
	}
	
//	@Override
//	public int compareTo(Employee o) {
//		return this.getEmpNo()-o.getEmpNo();
//	}
	
	@Override
	public int compareTo(Employee o) {
		return this.getEname().compareTo(o.getEname());
	}
	
}

public class MainClass {
	
	private static  ArrayList<Employee> getEmployeeList(){
		ArrayList<Employee> empList = new ArrayList<>();
		empList.add(new Employee(7928,"Amisha",55000.0,"Female",3.5));
		empList.add(new Employee(8029,"Ashok",45000.0,"Male",3.2));
		empList.add(new Employee(7930,"Akshay",25000.0,"Male",1.5));
		empList.add(new Employee(7731,"Bhavana",76000.0,"Female",5.5));
		empList.add(new Employee(9732,"Keerthi",45000.0,"Female",3.0));
		empList.add(new Employee(9833,"Vijay Gopal",105000.0,"Male",6.5));
		empList.add(new Employee(8034,"Vijay",35000.0,"Male",1.5));
		empList.add(new Employee(7635,"Vinitha",45000.0,"Female",3.0));
		empList.add(new Employee(6736,"Vignesh",125000.0,"Male",6.7));
		empList.add(new Employee(7937,"Ananya",119000.0,"Female",7.1));
		
		return empList;
	}

	public static void main(String[] args) {
		List<Employee> lstEmp = getEmployeeList();
		Collections.sort(lstEmp);
		
		// for each loop
		System.out.println("The Employee after the sorting based on the Employee ID = ");
		for(Employee e:lstEmp) {
			System.out.println(e);
		}
	}

}
=====================================
Limitation with Comparable<T> Interface:
========================================
-> the sorting on the list objects possible based on the single property only.
==============================================
Comparator<T> Interface:
=========================
-> when we want to sort list objects based on multiple properties, we need "Comparator<T> interface".

package package1;

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


class Employee{
	private int empNo;
	private String ename;
	private double salary;
	private String gender;
	private double experience;
	
	// creating the constructor for initializing class data members
	
	public Employee(int empNo, String ename, double salary, String gender, double experience) {
		super();
		this.empNo = empNo;
		this.ename = ename;
		this.salary = salary;
		this.gender = gender;
		this.experience = experience;
	}
	
	// defining setters and getters

	public int getEmpNo() {
		return empNo;
	}

	public void setEmpNo(int empNo) {
		this.empNo = empNo;
	}

	public String getEname() {
		return ename;
	}

	public void setEname(String ename) {
		this.ename = ename;
	}

	public double getSalary() {
		return salary;
	}

	public void setSalary(double salary) {
		this.salary = salary;
	}

	public String getGender() {
		return gender;
	}

	public void setGender(String gender) {
		this.gender = gender;
	}

	public double getExperience() {
		return experience;
	}

	public void setExperience(double experience) {
		this.experience = experience;
	}
	
	// generate toString()

	@Override
	public String toString() {
		return "Employee [empNo=" + empNo + ", ename=" + ename + ", salary=" + salary + ", gender=" + gender
				+ ", experience=" + experience + "]";
	}
}

class EmpnoComparator implements Comparator<Employee>{
	
	@Override
	public int compare(Employee o1, Employee o2) {
		return o1.getEmpNo() - o2.getEmpNo();
	}
}

class SalaryComparator implements Comparator<Employee>{

	@Override
	public int compare(Employee o1, Employee o2) {
		return (int)(o1.getSalary() - o2.getSalary());
	}
	
}

public class MainClass {
	
	private static  ArrayList<Employee> getEmployeeList(){
		ArrayList<Employee> empList = new ArrayList<>();
		empList.add(new Employee(7928,"Amisha",55000.0,"Female",3.5));
		empList.add(new Employee(8029,"Ashok",45000.0,"Male",3.2));
		empList.add(new Employee(7930,"Akshay",25000.0,"Male",1.5));
		empList.add(new Employee(7731,"Bhavana",76000.0,"Female",5.5));
		empList.add(new Employee(9732,"Keerthi",45000.0,"Female",3.0));
		empList.add(new Employee(9833,"Vijay Gopal",105000.0,"Male",6.5));
		empList.add(new Employee(8034,"Vijay",35000.0,"Male",1.5));
		empList.add(new Employee(7635,"Vinitha",45000.0,"Female",3.0));
		empList.add(new Employee(6736,"Vignesh",125000.0,"Male",6.7));
		empList.add(new Employee(7937,"Ananya",119000.0,"Female",7.1));
		
		return empList;
	}

	public static void main(String[] args) {
		List<Employee> lstEmp = getEmployeeList();
		Collections.sort(lstEmp,new EmpnoComparator());
		
		// for each loop
		System.out.println("The Employee after the sorting based on the Employee ID = ");
		for(Employee e:lstEmp) {
			System.out.println(e);
		}
		
		Collections.sort(lstEmp,new SalaryComparator());
		System.out.println("The Employee after the sorting based on the Employee Salaries = ");
		for(Employee e:lstEmp) {
			System.out.println(e);
		}
	}

}