java is a great language
1. simplicity: it is quiet simple (in comparison to c and c++)
humans make mistakes. the more complex a system is, the more mistakes will be made (even by a doctor professor so und so), the more likely an engineered system fails.
simplicity is VERY important if one wants to avoid software bugs/mistakes.
but with increasing demands for functionality (one box must DO EVERYTHING it could) complexity also increases -> more likely to be full of errors & bugs.
2. because with eclipse and it’s debugging capabilities (watch expressions) it (usually) does, what programming languages and computers in general are supposed to do:
show a human EASILY where they made some logic-mistakes/typos.
in PHP, there is no „real“ debugger, xdebug often simply does not „start“. because php probably never was designed to be grafically debugged.
3. compared to flex / actionScript the compile time is MUCH shorter, this is great when it comes to big projects.
but in every big project, no matter what language, a modular-structure should be used instead of a monolithic structure.