Klout Java Wrapper is an interface for the Klout API.
In order to use the API you need to first acquire an API key from the Klout website (http://developer.klout.com/member/register).
You can easily use it by downloading klout-java-wrapper.jar and attaching it to your project.
See the javadoc for more details.
Klout k = new Klout("your api key");
// retrieves klout id with twitter screen name
String[] data = k.getIdentity("jtimberlake", Klout.TWITTER_SCREEN_NAME); // contains ["635263", "ks]
// retrieves klout id with twitter id
String[] d = k.getIdentity("500042487", Klout.TWITTER); // contains ["54887627490056592", "ks"]
// gets user with klout id
User u = k.getUser("635263");
double score = u.score();
Topic[] topics = u.getTopics();
User[] influencers = u.getInfluencers();
User[] influencees = u.getInfluencees();