Hello! PHP

Hello, i'm working with PHP, and i need use a classes that this company have developed in java, can i use it from php? ...yes, i know that i can, but, when i make the configuration of the php.ini, run the hello example, all rights, but, when i make a class that use a frame of awt, for show a window, doesn't work, WHY?, the errors are, of Null pointer, and not found classes, but?, i need copy all classes of the basic structure of java, in my java.classpath?...where i can found more info? :-) Robert