New to Java

I'm busy writing algorithms for a large website planned for release in the next year or so.

This is my dilemma.
I have been programming a lot in Java recently and am familiar with all the concepts that I need to cover for this website, however I am not that keen to use Java. Along with this website I'm designing two software programs for use on Desktops (mainly windows, but may expand to Java MIDP (for cellphones), or to Linux, so that cheap systems can use the software). Java is the only language I know, besides HTML. As for database I have only worked with access, but will shift to mySQL soon, that isn't too much of a problem.

This is why I don't want to use Java:
* Applets and SECURITY problems all the time.
(Will I have any security issues if the applet is not signed, but I'm connecting to a web database?)
When I connect to a local DB, I get security issues.
* Java applets cannot be used on Opera Mini, phone browsers etc. (I want to design a Mobi Site)

Which language do you reckon I learn, I am really stuck at a fork in the road. Java is so easy to use and functional once you know what you're doing. What it seems is I should be using PHP for the site, JavaScript to manipulate the dates and data, Java for the cellphone application, then C++ for the desktop app. I could use Java for the desktop app, but it seems as if when I run jar files on some computers they run fine, on others, they say "main class not found, program will now exit". Is JavaScript and PHP powerful enough for manipulating dates, creating your own functions and methods etc.?

Also is it worth using a content management system such as Joomla etc. which mostly seem to use PHP?