How do you compile PHP in Java?

I am making a project, a web server. I want to do as much as I can from scratch, so I designed listeners which can transmit basic information ( html ) to the client, then terminate the connection. Unfortunately, I can't find out how to use POST with this. I also want to make the pages my software hosts to be dynamic, so I want to support PHP. I've Googled for a while, but can't find anything. I don't know if there is some library or something, but basically I want to compile the PHP into HTML code.