In my ongoing attempts to use various Java libraries, without writing any Java myself, I have trying  Apache Tika.
(http://tika.apache.org/1.4/api/org/apache/tika/Tika.html). With the tika jar on the classpath I hoped the following would work:

import module namespace tika = "java:org.apache.tika.Tika";
declare namespace File="java:java.io.File";
let $file :=File:new("xx.pdf")
return tika:parse($file)

It generates the error
Signature 'org.apache.tika.Tika.parse' is ambiguous

Which maybe it is from some perspectives :-). I hoped some type information might be available in the $file variable to resolve this, but it appears not.
I was wondering about the possibility of  using Java type at the XQuery level e.g.
let $file as java:java.io.File :=File:new("xx.pdf")