It has a really nice REST API interface as well. One of the ways that API is expressed is through XML, but there are also JSON and Python versions (yes, the API sends you Python code in one version!)
Access the same data as Python for Python clients. This can be parsed into Python object as eval(urllib.urlopen("...").read()) and the resulting object tree is identical to that of JSON. However, when you do this, beware of the security implication. If you are connecting to a non-trusted Hudson, the server can send you malicious Python programs.
Amazingly for a Java app, I didn't have to touch a single XML file. Everything can be configured through the web interface. Fantastic!