Generate MD5 hash in Java

Is there any method to generate MD5 hash of a string in Java?

Need memory efficient way to store tons of strings (was: HAT-Trie implementation in java)

I am working with a large set (5-20 million) of String keys (average length 10 chars) which I need to store in an in memory data structure that supports the following operation in constant time or near constant time:

jQuery IF var = value or #id clicked

I have the .live aspect working now so if links are clicked, my function is executed, but I'm trying to figure out how include an option for a direct link to the content as well. Something like this: