Apps Can't installed my application

[zhtzeng]

Dears,

I write an application and put it into the /system/app on my device.
However, I can't see my application appeared in the application list.
How do I know why my application is not in the application list?
If I can telnet to my device, is any debug messages for checking?

Besides, since the whole system is build by myself.
I thought I can print some debug messages in the android source code to check why my application is illegal.
Anyone can give me a clue which file is used to monitor /system/app?


Thank you.

BR,
Kevin