Here is a java examples that stores employees data into arraylist and sort the employees according to id, first name, last name and salary.

import java.util.*;

class Employee{
int id;
public int salary;
public String fname;
public String lname;
public static int count = 0;
public Employee(){}
public Employee(int id,String fname,String lname,int salary) {
super();
this.id=id;
this.fname = fname;
this.lname=lname;
this.salary = salary;
}
public int getId(){
return id;
}
public String getFname(){
return fname;
}
public String getLname() {
return lname;
}
public int getSalary(){
return salary;
}
}
class FNameComparator implements Comparator{
     public int compare(Object emp1, Object emp2){    
        String emp1Name = ((Employee)emp1).getFname();        
        String emp2Name = ((Employee)emp2).getFname();
        return emp1Name.compareTo(emp2Name);
       }
 }
 class LNameComparator implements Comparator{
     public int compare(Object emp1, Object emp2){    
        String emp1Name = ((Employee)emp1).getLname();        
        String emp2Name = ((Employee)emp2).getLname();
        return emp1Name.compareTo(emp2Name);
       }
 }
 class IdComparator implements Comparator{

    public int compare(Object ob1, Object ob2){
        int ob1Id = ((Employee)ob1).getId();        
        int ob2Id = ((Employee)ob2).getId();

        if(ob1Id > ob2Id)
            return 1;
        else if(ob1Id < ob2Id)
            return -1;
        else
            return 0;    
    }
 }
class SalaryComparator implements Comparator{
    public int compare(Object emp1, Object emp2){
        int sal1 = ((Employee)emp1).getSalary();        
        int sal2 = ((Employee)emp2).getSalary();

        if(sal1 > sal2)
            return 1;
        else if(sal1 < sal2)
            return -1;
        else
            return 0;    
    }
}

public class ArrayListOfEmployees{
public static void main(String[] args) throws Exception{
List<Employee> list = new ArrayList<Employee>();
list.add(new Employee(2,"Victor","Desouza",10000));
list.add(new Employee(4,"Jennie","Hook",20000));
list.add(new Employee(1,"John","Flower",15000));
list.add(new Employee(7,"Daniel","Austen",12000));
list.add(new Employee(9,"Angelina","Paul",16000));
list.add(new Employee(10,"Maria","Agassi",22000));
list.add(new Employee(3,"Zenn","Bekham",25000));
list.add(new Employee(8,"Andy","Flower",22000));
list.add(new Employee(6,"George","Hook",25000));
list.add(new Employee(5,"Chris","Harris",22000));

continues..

System.out.println(" ");
    int count=0;
    int salary=0;
                   System.out.println("Employee Data sorted according to First Name:");
                    Collections.sort(list,new FNameComparator());
                    for(Employee data: list){
                    System.out.println(data.getId()+"\t"+data.getFname()+"\t"+data.getLname()+"\t"+data.getSalary());
                    } 
                    System.out.println("Employee Data sorted according to Last Name:");
                    Collections.sort(list,new LNameComparator());
                    for(Employee data: list){
                    System.out.println(data.getId()+"\t"+data.getFname()+"\t"+data.getLname()+"\t"+data.getSalary());
                    } 
                    System.out.println("Employee Data sorted according to ID:");
                    Collections.sort(list,new IdComparator());
                    for(Employee data: list){
                    System.out.println(data.getId()+"\t"+data.getFname()+"\t"+data.getLname()+"\t"+data.getSalary());
                    } 
                    System.out.println("Employee Data sorted according to Salary:");
                    Collections.sort(list,new SalaryComparator());
                    for(Employee data: list){
                    System.out.println(data.getId()+"\t"+data.getFname()+"\t"+data.getLname()+"\t"+data.getSalary());
                    } 

       }
    }