How to access SAP database tables with Java (Jco)

Hi!

I need to develop a Java Client for SAP with access to the SAP database. Is there a way to do this directly in Java (the db access) or do I have to use some ABAP logic in between to get the information to the java client? If so, are there any existing ABAP functions to read AND write db tables? Or do I have to create my own wrappers for each table I need to read and write?

Thanks,

Konrad