Instantiate Dictionary<T, U> in Java error

Question

In C#

Dictionary<String, String> dictionary = new Dictionary<String, String>(); 

In Java, this errors with

Cannot instantiate the type Dictionary

What could be wrong?

In my code this follows with

dictionary.put("vZip", jsonUdeals.getString("vZip")); 

I know this sounds too trivial. But I am at a loss!
If Dictionary doesn't do it(which I strongly suspect by now), then which DataStructure to use.

Answer 1

Dictionary is an abstract class in Java. It is also obsolete; you should use the Map interface instead; something like:

Map<String,String> map = new HashMap<String,String>(); 

Note that HashMap<K,V> is a concrete class, but we're assigning it to a Map<K,V> reference, which is an interface. This is the recommended style in Java, because it allows you to switch HashMap for e.g. Hashtable at a later stage, without having to change everything.

Answer 2

Use a HashMap as follows:

Map<String, String> dictionary = new HashMap<String, String>();