Things to consider are:

Speed

Maintenance free

compatibility with other code or scripts

That really depends on application... For heavy duty applications Java is good for visual applications, for most web application php is more then enough and will be faster then Java in many applications. For basic page opperations, like form validations javascripts are good because they don't have to check validations against a server taking up more resources.

There are things that flash and java can do in seconds that php never can do however if you make your entire webpage outta flash or java its gonna run slower then PHP if your application is like an online job application form.

So it depends on what you want to do.