The UDF code and the testing program are both written in Java.

I'm using Eclipse 3.0.1 in Windows XP.

Here is the UDF:
========================================================
import java.sql.SQLException;
import COM.ibm.db2.app.UDF;

public class TextFuncs extends UDF {

   public static String reverse (String input)
   throws SQLException {

    try {
        StringBuffer reversedStringBuffer = new StringBuffer();
         for (int ix=input.length(); ix>0; ix--) {
             reversedStringBuffer.append(input.substring(ix-1, ix));
         }

    /* Set the output string to be the reverse of the input string. */
     return(reversedStringBuffer.toString());
     }
    catch (Exception excp) {
     throw new SQLException("Invalid Operation", "38702");
     }
   }
}
========================================================

Here is the UDFDriver program:
========================================================
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

import javadb2.JDBC01;

public class UDFDriver {

   private final String CLASS_NAME = getClass().getName();

   private Connection conn01 = null;

   public static void main(String[] args) {

       new UDFDriver();
   }

   /**
    *  Constructor
    */
   public UDFDriver() {
       super();

       System.out.println("Welcome to " + CLASS_NAME + "!\n");

       System.out.println("\nLoad the JDBC driver....");
       loadDriver();

       System.out.println("\nConnect to the database....");
       connectToDatabase();

       System.out.println("\nExecute functions....");
       executeFunctions();
   }

   /**
    * Load the JDBC driver.
    */
   private void loadDriver() {

       String METHOD_NAME = "loadDriver()";

       String jdbcDriverName = "COM.ibm.db2.jdbc.app.DB2Driver";

       /* Load the JDBC driver. */
       try {
           Class.forName(jdbcDriverName);
       } catch (ClassNotFoundException excp) {
           System.err
                   .println(CLASS_NAME
                           + "."
                           + METHOD_NAME
                           + " - Encountered ClassNotFoundException while
attempting to load JDBC driver "
                           + jdbcDriverName + ". Error: " + excp);
           excp.printStackTrace();
           System.exit(16);
       }
   }

   /**
    * Get a connection to the database.
    *
    */
   private void connectToDatabase() {

       String METHOD_NAME = "connectToDatabase()";

       /* Initialize the variables used to get the connection. */
       String databaseName = "sample";
       String url = "jdbc:db2:" + databaseName;
       String loginName = "db2admin";
       String password = "db2admin";

       /* Connect to the database. */
       try {
           conn01 = DriverManager.getConnection(url, loginName, password);
       } catch (SQLException sql_excp) {
           System.err.println(CLASS_NAME + "." + METHOD_NAME
                   + " - Encountered SQLException on connect to URL " + url
+ ". Error: "
                   + sql_excp);
           sql_excp.printStackTrace();
           System.exit(16);
       }

       /* Set autocommit off. */
       try {
           conn01.setAutoCommit(false);
           System.out.println("Turn off autocommit...");
       } catch (SQLException sql_excp) {
           System.err.println(CLASS_NAME + "." + METHOD_NAME
                   + " - Encountered SQLException on attempt to turn
autocommit off. Error: "
                   + sql_excp);
           sql_excp.printStackTrace();
           System.exit(16);
       }
   }

   private void executeFunctions() {

       String METHOD_NAME = "executeFunctions()";

       String queryTableSQL =
           "select lastname, rhino.reverse(lastname) " +
           "from rhino.employee " +
           "where workdept = 'D21'";

       /*
        * Query the demonstration table to get information about certain
        * employees.
        */
       Statement queryTableStmt = null;
       ResultSet rs01 = null;
       try {
           queryTableStmt = conn01.createStatement();
           rs01 = queryTableStmt.executeQuery(queryTableSQL);
       } catch (SQLException excp) {
           System.err.println(CLASS_NAME + "." + METHOD_NAME
                   + " - Encountered SQLException while trying to get
information from "
                   + "Employee table. Error: " + excp);
           excp.printStackTrace();
           System.exit(16);
       }

       /*
        * Print a title line above the result set. The static method pad()
is
        * used to align the column titles and underlines.
        */
       String spaces = "   ";
       System.out.println(JDBC01.pad("LASTNAME", ' ', 'T', 15) + spaces
               + JDBC01.pad("REVERSED", ' ', 'T', 15));
       System.out.println(JDBC01.pad("--------", ' ', 'T', 15) + spaces
               + JDBC01.pad("--------", ' ', 'T', 15));

       /* Initialize the host variables used for handling the result set.
*/
       String lastname = null;
       String reversed = null;

       /*
        * Print each line of the result set. The static method pad() is
again used
        * to align the data values with the column titles.
        */
       try {
           while (rs01.next()) {
               lastname = rs01.getString(1);
               reversed = rs01.getString(2);
               System.out.println(JDBC01.pad(lastname, ' ', 'T', 15) +
spaces + JDBC01.pad(reversed, ' ', 'T', 15));
           }
       } catch (SQLException sql_excp) {
           System.err.println(CLASS_NAME + "." + METHOD_NAME
                   + " - Encountered SQLException while reading Employee "
                   + "table. Error: " + sql_excp);
           sql_excp.printStackTrace();
           System.exit(16);
       }

       /* Close the result set, dispose of the statement, and commit. */
       try {
           rs01.close();
           queryTableStmt.close();
           conn01.commit();
       } catch (SQLException sql_excp) {
           System.err.println(CLASS_NAME + "." + METHOD_NAME
                   + " - Encountered SQLException while closing Employee"
                   + " result set, closing statement, or committing. Error:
" + sql_excp);
           sql_excp.printStackTrace();
           System.exit(16);
       }
   }
}
========================================================

Please note that I'm not actually having any problems with my UDF; it is
very simple and works perfectly. I just want to figure out how to step
through the code in the Eclipse debugger in case I have problems with more
complex UDFs later on.

Rhino