Background

I have two services that need to communicate with each other over a message queue. One is a legacy service written in PHP and the other is in Java. Sooner than later, the PHP service will be rewritten in Java. The current way they communicate with each other is to write to a shared database, which the other service polls. This is what I'm trying to get away from and replace with a message queue.

Problem

The communication I'm working on right now is from the PHP service to the Java service. It needs to send a relatively complex object (strings and and integers and lists and maps of strings and integers). Ideally, the solution would be workable in PHP and ideal in Java, as that's going to be the legacy of this project.

Possible Solutions

1.