Java Hashtables.

Question

Ok, the API documentation for Java Hashtables says that they use "open hashing". This means you can store two values under the same key- the storage space for each key is in some sort of collection, and it can be added to the collection. So, basically, that implies that code such as:
java.util.Hashtable h = new java.util.Hashtable();
h.put("A", "ABC");
h.put("A", "DEF");
System.out.println(h.get("A"));
System.out.println(h.get("A"));
System.out.println(h.get("A"));
would add bot ABC and DEF to the hash key entry. Unfortunately, the get statements above all print out "DEF".
The way I would get around it would be something like this:
Hashtable h = new Hashtable();
MyClass myInstance = new MyClass(1);
//Assume that MyClass.getKey() returns the desired Key for the hashtable.
if (h.containsKey(myInstance.getKey()){
h.put(myInstance.getKey(new LinkedList(myInstance));
else{
((List)(h.get(myInstance.getKey())).add(myInstance);
(I understand that ArrayList probably isn't the most efficient collection to use here, but I'm just trying to show the basic workaround.)
I have no problem working around this, however, the API documentation for it says,
"Note that the hash table is open: in the case of a "hash collision", a single bucket stores multiple entries, which must be searched sequentially."
This implies that the Hashtable entries are coded to automatically store multiple items. But, I don't see that implemented.
In fact, if you think about it, if you have to store your own collections in the hashtable's entry table, there really isn't anything at all in the actual implementation of the hashtable class itself that makes it open.
Like I said, I have no significant opposition to implementing such a workaround, however, the API leads me to believe that hashtable is implemented in a way that doesn't require me to, although the methods contained in it seem to show otherwise.
Is there a better way? Or is the API inconsistent? Or is my interpretation of "open" and "closed" hashing off-beat?
Thanks for the help guys,
Scott

Answer 1

Ok, the API documentation for Java Hashtables says
that they use "open hashing". This means you can
store two values under the same key- No, not under the same key, but under the same hashCode.
the storage
space for each key is in some sort of collection, and
it can be added to the collection. So, basically,
that implies that code such as:
java.util.Hashtable h = new java.util.Hashtable();
h.put("A", "ABC");
h.put("A", "DEF");
System.out.println(h.get("A"));
System.out.println(h.get("A"));
System.out.println(h.get("A"));
would add bot ABC and DEF to the hash key entry.No, that's not correct. The key has be to unique, and "A".equals("A") == true.
Kaj