Java can be used with servers and databases, it's usually for real time usage. PHP is slightly delayed in a way compared to Java. When you say PHP seems kind of weak compared to C++, remember that they are used for two very diiferent things. The project your looking at, could be done in either PHP or Java, but would be best written in PHP w/MYSQL. Depending on what functions you want the program to perform, depends on what language you woudl choose. As said, Java needs the runtime, whereas php is all server side. Unless there is something you need that can't be done in PHP, then there would be no reason to do this in Java.
Anyways, Have fun
