As I dont have PHP expertise ,Iam thinking writting porter code for unsupported platform in Java specifically Hibernate , As it's all about mapping tables from one platform to another .
Will it be a Good Idea?
the porter is standalone. If you can't interpret the portercode how are you going to translate it to Java?
At best you are goign to need a good understanding of the data model and schema.
Php is not really not hat hard, and this is an automation script it doesn't have to be perfect.
grep is your friend.
No, that won't work. A "package" as we call them gets bundled with the rest of the PHP code to distribute. There's no mechanism to include non-PHP code.
You could built an entirely Java-based version of the Porter as long as the end result was a text file in the same format. That said, I have no interest in such a system and think it would be a massively redundant effort.
A better strategy would be to dump your existing database to a PHP-enabled webserver. I think it would take far less time for you to parrot existing packages in a language you don't have experience in, adapting them to meet the needs of this new system, then to start Porter over in Java.