[Java] How to implement hash? Map or Hashmap?

When I wanted to write code with a "hash table" that I learned from a data structure book, I was not sure what java class to use... I did some research and found that Hashmap is my best bet for most of my purposes. Hash table is a great invention. (source: http://www.quora.com/Who-invented-hash-tables)

I do not write multi-threaded application. And I just want to put items in the data structure and find things quickly with key...

You can declare a Hashmap object as follows:

Hashmap<String, String> hm = new Hashmap<String, String>();

You can change "String" to any type you want.

Next, you may want to put your key, value pairs into the hm obect as follows:

hm.put("KeyString1", "ValueString1");

If you find some value with your key value, you can do is as follows:

String s = hm.get("KeyString1");

Then s will get "ValueString1".

Finally, sometimes I want to iterate all the items in the Hashmap object, even though it is not a list. We can do that by using Iterator object as follows:

Iterator it = hm.entrySet().iterator();

while (it.hasNext()) {

Map.Entry pair = (Map.Entry)it.next();

String keyStr = pair.getKey();

String valueStr = pair.getValue();

}

Hope this will help you...