ConnectionBean fail with stress test. please assist.

Question

I am using the following to get connected to database.
package com.db;
import java.util.*;
import java.io.*;
import java.sql.*;
import javax.servlet.http.*;
public class ConnectionManager implements HttpSessionBindingListener
  private Connection connection;
  private Statement statement;
  private String driver = "";
  private String dbURL = "";
  private String login = "";
  private String password = "";
static public void main(String[] args)
      ConnectionManager cm = new ConnectionManager();
  } // main
public ConnectionManager()
       Properties Prop = new Properties();
       try {
          InputStream configStream = getClass().getResourceAsStream("/config/database.properties");
               Prop.load(configStream);
          configStream.close();
           } catch(IOException e) {
                  System.out.println("Error: Cannot laod configuration file ");
       driver =Prop.getProperty("driver");
       dbURL = Prop.getProperty("dbURL");
        login = Prop.getProperty("login");
        password = Prop.getProperty("password");
public void setDriver (String sDriver)
   if (sDriver != null)
       driver = sDriver;
public String getDriver ()
   return driver;
public void setDbURL (String sDbURL)
    if (sDbURL != null)
     dbURL = sDbURL;
public String getDbURL()
   return dbURL;
public void setLogin (String sLogin)
   if (sLogin != null)
      login = sLogin;
public String getLogin()
   return login;
public void setPassword (String sPassword)
   if (sPassword != null)
      password = sPassword;
private String getPassword()
   return password;
private void getConn ()
   try
      Class.forName(driver);
      connection = DriverManager.getConnection(dbURL,login,password);
      statement=connection.createStatement();
   catch (ClassNotFoundException e)
      System.out.println("ConnectionManager: driver unavailable");
      connection = null;
   catch (SQLException e)
      System.out.println("ConnectionManager: driver not loaded");
      connection = null;
public Connection getConnection()
   if (connection == null)
      getConn();
   return connection;
public void commit() throws SQLException
    connection.commit();
public void rollback() throws SQLException
    connection.rollback();
public void setAutoCommit(boolean autoCommit)
    throws SQLException
    connection.setAutoCommit(autoCommit );
public ResultSet executeQuery(String sql) throws SQLException
    if (connection == null || connection.isClosed())
        getConn();
    return statement.executeQuery(sql);
public int executeUpdate(String sql) throws SQLException
    if (connection == null || connection.isClosed())
        getConn();
    return statement.executeUpdate(sql);
public void valueBound(HttpSessionBindingEvent event)
    System.err.println("ConnectionBean: in the valueBound method");
    try
      if (connection == null || connection.isClosed())
        connection = DriverManager.getConnection(dbURL,login,password);
        statement = connection.createStatement();
    catch (SQLException e)
      e.printStackTrace();
      connection = null;
public void valueUnbound(HttpSessionBindingEvent event)
    close();
public void close()
   try
       if ( connection != null
            || !connection.isClosed())
        connection.close();
   catch (SQLException e)
      e.printStackTrace();
}This is what I use to test this code:
<%@ page import="java.sql.*" %>
<%@ page import="java.text.*" %>
<%@ page import="java.util.*"%>
<%@ page import="java.io.*" %>
<p>
Testing DBConnection Bean. <p>
<%
String sql="SELECT * FROM BS_PERSON" ;
com.db.ConnectionManager CM = new com.db.ConnectionManager();
ResultSet rset = CM.executeQuery(sql);
while (rset.next()) {
   out.println(rset.getString("PERSON_USERCODE") + "<br>");
%>When I stress test it, the code perform well for a while and then throw the following on Tomcat:
ConnectionManager: driver not loaded
ConnectionManager: driver not loaded
ConnectionManager: driver not loaded
Is there anything I could improve?
For application that has many database read/write, is there any open source connection program that uses connection pooling?
Thank you.

Answer 1

Thank you for the prompt response.
Yes. the code works and the data set gets return when I execute the code. It only fail with stress test after say 150-160 hits.
I have put in the printStack Trace and got the following:
ConnectionManager: driver not loaded
java.sql.SQLException: ORA-00020: maximum number of processes (150) exceeded
     at oracle.jdbc.dbaccess.DBError.throwSqlException(DBError.java:134)
     at oracle.jdbc.ttc7.TTIoer.processError(TTIoer.java:289)
     at oracle.jdbc.ttc7.O3log.receive1st(O3log.java:407)
     at oracle.jdbc.ttc7.TTC7Protocol.logon(TTC7Protocol.java:259)
     at oracle.jdbc.driver.OracleConnection.<init>(OracleConnection.java:346)
     at oracle.jdbc.driver.OracleDriver.getConnectionInstance(OracleDriver.java:468)
     at oracle.jdbc.driver.OracleDriver.connect(OracleDriver.java:314)
     at java.sql.DriverManager.getConnection(DriverManager.java:512)
     at java.sql.DriverManager.getConnection(DriverManager.java:171)
     at com.db.ConnectionManager.getConn(ConnectionManager.java:106)
     at com.db.ConnectionManager.executeQuery(ConnectionManager.java:154)
     at org.apache.jsp.dbconnection_jsp._jspService(dbconnection_jsp.java:76)
Could it be that I didn't specifically close the connection? How could I go about doing it?
Thank you.