Ytukyg

I want to store Objects in the Hash map as key and while Retrieving time i want a ascending order based on Employee id.and i dont want to use comparator or comaprable interfaces just sorting based on hashcode and equals method is it possible.

 public class Employee {



private String name;

private int id;



public String getName() {

    return name;

}



@Override

public int hashCode() {

    final int prime = 31;

    int result = 1;

    result = prime * result + id;

//  result = prime * result + ((name == null) ? 0 : name.hashCode());

    System.out.println("hashcode value :::"+result + "id :::"+id);

    return result;

}



@Override

public boolean equals(Object obj) {

    if (this == obj) {

        return true;

    }

    if (obj == null) {

        return false;

    }

    if (getClass() != obj.getClass()) {

        return false;

    }

    Employee other = (Employee) obj;

    if (id != other.id) {

        return false;

    }

    if (name == null) {

        if (other.name != null) {

            return false;

        }

    } else if (!name.equals(other.name)) {

        return false;

    }

    return true;

}



public void setName(String name) {

    this.name = name;

}



public int getId() {

    return id;

}



public void setId(int id) {

    this.id = id;

}

}

package info.test;



 import java.util.HashMap;

 import java.util.Map;

 import java.util.Set;



  public class MainClass {



public static void main(String args) {



    Employee e1 = new Employee();

    e1.setId(2);

    e1.setName("name");

    Employee e2 = new Employee();

    e2.setId(35);

    e2.setName("name");

    Employee e3 = new Employee();

    e3.setId(4);

    e3.setName("name");

    Employee e4 = new Employee();

    e4.setId(3);

    e4.setName("name");



    Map<Employee, String> linkedHashMap = new HashMap<Employee,String>();

    linkedHashMap.put(e1, "e");

    linkedHashMap.put(e2, "e");

    linkedHashMap.put(e3, "e");

    linkedHashMap.put(e4, "e");





     Set<Employee> keySet = linkedHashMap.keySet();

     for(Employee e:keySet){

        //System.out.println(e.getId()); 

     }





}}

its work some samples like

 if give ids like 2 55 4 3  and output is 2 3 4 55

and for some samples its not working

 2 35 4 3  and output 2 35 3 4

You were so close. This

Map<Employee, String> linkedHashMap = new HashMap<Employee,String>();

should be LinkedHashMap which preserved insertion order like

Map<Employee, String> linkedHashMap = new LinkedHashMap<>();

If it should be sorted in natural order use a TreeMap like

Map<Employee, String> linkedHashMap = new TreeMap<>();