Is there any nice class for this situation?

Hello guys!

I have an problem with a HashMap when I iterate over the keys.
Below is an example cod:

package test;

import java.util.HashMap;
import java.util.Iterator;
import java.util.Set;

public class ScrapTest {

    /**
    * @param args
    */
    @SuppressWarnings("unchecked")
    public static void main(String[] args) {
        HashMap hashmap = new HashMap();
        hashmap.put("a", "object 1");
        hashmap.put("c", "object 2");
        hashmap.put("b", "object 3");
        hashmap.put("f", "object 4");
        hashmap.put("g", "object 5");
        hashmap.put("e", "object 6");
       
        Set keys = hashmap.keySet();
        Iterator iterator = keys.iterator();
        while( iterator.hasNext() )
        {
              String key = (String)iterator.next();
              System.out.println(key);
        }

    }

}

This gave me this output:
f
g
e
b
c
a

I want to get this output (the order that they are inserted):
a
c
b
f
g
e

Is there a way to manage this?
Perhaps whit some other class?

So if you guys got any ideas please let me know!
Best regards
Fredrik