You must create a server process class that implements the IServerProcess interface, and implements the method IServerProcess.process().

The process() method contains the processing logic of the RFC server function you intend to offer. Each process() method reads the import and table parameter information and processes the data. Then, it uses the export and table parameters to return the results of the processing.

public class ComputeTaxProcess implements com.sap.rfc.IServerProcess

{
    public ComputeTaxProcess()
    {
        // constructor actions
    }
public void process(IServerFunction serverFunction)
    {
        // Here you put in the code that reads import
        // and table parameter data, and processes the data
com.sap.rfc.ISimple _name =
            serverFunction.getImportParam("NAME");
        com.sap.rfc.ITable _expensesTable =
            serverFunction.getTableParam("EXPENSE_LIST");
   }
}