Java is a programming language that is used almost everywhere. It can be in server side web pages (eg: JSP) or in the browser (Java applet) or in desktop software, mobile phones etc.
PHP is used mainly on the server side, so when you say PHP, you most likely mean server side PHP.
JSP is a Java framework (the most popular of many I believe), used to building Java server side pages.
Here is the JSP forum on this site:
You could get a lot of help with JSP there.
Relation to Java:
But since your host allows you to use JSP and edit it, then there is really no need for a separate server.
I think you should let go of the PHP review script you have, and just focus on a JSP solution - either getting a JSP review script or having someone code a custom solution. This is the simplest solution, and the one that will get you the best SEO results.
Might be a little late, but there is a PHP to Java Script converter available at
Also, if you waned an automated tool to convert from php to java, you could use
The Runtime Covnerter (online PHP to Java Conversions)
There's no online conversion site for the PHP to Java Script. You have to run it locally.