L.A.M.P. refers to a toolset consisting of Linux + Apache + MySQL + PHP|Perl|Python|Postgresql... providing a powerful framework for rapid development of robust solutions. Each component is open source and has proven to be enterprise ready.
Java isn't open source, never has been and you can see how it's deviated from the needs of the majority of developers... in steps php.
Marc Andreessen, Netscape creator, speaks at the Zend/Php Conference on Java's shortcomings and sees php as it's successor. more