On one of my integration projects, I actually had to use JAVA to handle XML data coming in and from within the JAVA code, had to use a system call out to an ancient PERL script which would generate Excel spreadsheets based on data in the db from the XML component...not pretty but doable since PERL was used to perform some system level tasks and JAVA was taking care of the front-end data processing.

Using PHP / JAVA however in my opinion does not make too much sense since I don't really see any way that the two can complement each other - in fact, if both are used for web development you would need to run both an Apache Tomcat Server for your servlet container and also an actual Apache Web Server in order for PHP to be handled

Cheers,

Mike