Java Database connection

"Yogi" <yogi@THRWHITE.remove-dii-this>
Wed, 27 Apr 2011 15:23:14 GMT

I am new to java and db connection pooling. I tried using Apache's
DBCP for connection pool for my web application. Was trying to do
similar thing for a standalone server (not a web based). I tried
using DBCP but i am getting strange results. In my string variables,
i am getting "???" as output whereas for int variables i am getting
correct values when i m trying to read from database.

Here is the snippet code:

I have a package "com.engine". In this package,
1. I am having EngineDBConnection which is responsible to pool
2. "EngineDBManager" class takes care of process user's queries and
calls required procedures and db constructs
3. "Test" is the actual code which runs and gets required fields and
displays to client.


package com.engine;

import org.apache.commons.dbcp.BasicDataSource;
import javax.sql.DataSource;
import java.sql.Connection;
import java.sql.SQLException;

public class EngineDBConnection {

    private static String dbURL = "jdbc:oracle:thin:user/pwd@localhost:
    static DataSource dataSource = null;
    public static void createDataSource(){
        // create db connection in constructor
        dataSource = setupDataSource(dbURL);

    public static Connection getConnection() {
        Connection conn = null;
        try {
            if (dataSource != null) {
                conn = dataSource.getConnection();
            } else {
                return null;

        } catch (Exception e) {
        return conn;

    public static DataSource setupDataSource(String connectURI) {
        BasicDataSource ds = new BasicDataSource();
        System.out.println("coming in setupdatasource");
        return ds;

    public static void shutdownDataSource(DataSource ds) throws
SQLException {
        BasicDataSource bds = (BasicDataSource) ds;

package com.engine;
import java.sql.CallableStatement;
import java.sql.Connection;
import java.sql.Types;
import java.util.ArrayList;
import java.util.List;

import oracle.sql.STRUCT;

import com.dbobjs.DInfo;

public class EngineDBManager {

    public static List<DInfo> getDInfo(){
           Connection conn = null;
           conn = EngineDBConnection.getConnection();
           CallableStatement cst = null;
           List<DInfo> dList = null;

           int result = -9;
                cst = conn.prepareCall("begin pkg_admin.p_get_info(?,?);
                cst.registerOutParameter(1, Types.ARRAY, "VARRAY_DINFO");
   cst.registerOutParameter(2, Types.INTEGER);
                result = cst.getInt(2);
   if (result != 0) {
                    return null;

                Object structs[] = (Object[])(cst.getArray(1).getArray());
                dList = new ArrayList<DInfo>(structs.length);

                for (int i = 0; i < structs.length; i++) {
                 DInfo map = (DInfo)DInfo.readStruct((STRUCT)structs[i]);
           }catch (Exception e) {
           return dList;

package com.engine;

import java.sql.CallableStatement;
import java.sql.Connection;
import java.sql.Types;
import java.util.List;

import com.dbobjs.DInfo;
public class Test {

   public Test(){

   public static void main(String args[]){
   Test t1 = new Test();

       List <DInfo> dList = EngineDBManager.getDInfo();

       DInfo d = null;
       if (dList == null){
          System.out.println("DInfo is null");
           for (int i=0;i < dList.size(); i++){
                 d = (DInfo) dList.get(i);
                 System.out.println("Id=" + d.getDID() + " Desc=" +


when I am printing output in "Test" class, I am getting correct Id but
Desc is giving me "???". I tried executing oracle procedure from
oracle and it is working perfectly fine. Am i missing something
here? Please help.

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