How do I create a hash table in Java?

Question

What is the most straightforward way to create a hash table (or associative array...) in Java? My google-fu has turned up a couple examples, but is there a standard way to do this?

And is there a way to populate the table with a list of key->value pairs without individually calling an add method on the object for each pair?

Answer 1

Map map = new HashMap();
Hashtable ht = new Hashtable();

Both classes can be found from the java.util package. The difference between the 2 is explained in the following jGuru FAQ entry.

Answer 2

You can use double-braces to set up the data. You still call add, or put, but it's less ugly:

private static final Hashtable<String,Integer> MYHASH = new Hashtable<String,Integer>() {{
    put("foo",      1);
    put("bar",      256);
    put("data",     3);
    put("moredata", 27);
    put("hello",    32);
    put("world",    65536);
 }};