Using an array list as a hash map value

Question

Hi,
I have an object which has a "properties" field, which contains certain data for that object.
Most of the time the key/values are both Strings, but in at least one instance, the key is a string, the value needs to be an array list.
The Map is declared as HashMap<String, Object>
when I populate the map, and then attempt to retrieve its value, it seems to work correctly.
But when I try to retrieve the arrayList from another object, using its getter, it doesn't work,
IOW, if I have code like this:
// object created from outside the class where the map is populated
ExampleObject eo = new exampleObject();
eo.getProperties.get("string value that is a key for the map. ");
// if I try to determine the class the value is,
System.out.println("class: " + eo.getProperties,get("string value that is a key for the map. ").getClass());
// the code above indicates the object is a string. I googled and found a suggestion on this forum, that instead of making the map value an arrayList, I should create an object that contains an array list as a field, and then use that new object as the map value. I tried that and had the same problem.
any idea what I'm doing wrong? Hope that's clear...
thanks!!
bp
Edited by: badperson on Aug 13, 2008 9:38 AM

Answer 1

threw this together and it worked fine, so something else is screwed up in my code.
import java.util.*;
public class MapTester {
     private HashMap<String, Object> testMap;
     private ArrayList testList;
     public ArrayList<String> createList(String listName){
          System.out.println("creating list");
          testList = new ArrayList<String>();
          testList.add(listName + " line one");
          testList.add(listName + " line two");
          testList.add(listName + " line three");
          return testList;
     public HashMap<String, Object> createMap(String key, Object value){
          System.out.println("populating map");
          testMap = new HashMap<String, Object>();
          testMap.put(key, value);
          return testMap;
     public static void main(String[] args){
          MapTester mapTester = new MapTester();
          mapTester.createList("List 1");
          mapTester.createMap("listKey", mapTester.getTestList());
          System.out.println("retrieving arrayList");
          System.out.println("map value is type: " + mapTester.getTestMap().get("listKey").getClass());
     public ArrayList getTestList() {
          return testList;
     public HashMap<String, Object> getTestMap() {
          return testMap;
}thanks for the replies
bp