Permissions within a function

I'd like some views on the following issue.

The pljava function call handler will resolve a class name using a 
loader that in turn uses a specific table in the PostgreSQL database. 
Hence, the caller of the function must have select permissions on that 
table or the function will fail. I would like to prevent this somehow 
but I don't know how to go about that. Is there any way to bypass the 
permissions when I do an SPI call from within a call handler somehow?

Regards,
Thomas Hallgren