Using database connection in a servlet and get errors after 8 hours

Question

Hey,
I'm running a poker script using applet/servlets and it works great. But for some reason about about 8 hours that database layer stops working. At first I thought it was the connections to mySQL that were timing out (because im using connection pooling) but after turning pooling off (I now create the connection each time) I'm still seeing that same error (I can create a connection but when I do an action ex. like a select statment I get an error). What i'm wondering could it be that the driver I load with Class.forName() some how unloads it's self after x amount of time not being used? Not sure if that is it but if anyone could give me some insight that would be great. The Error i recieve is below:
INFO: Database Event:DatabaseController: Error executing database query.
ERROR: Communications link failure due to underlying exception:
** BEGIN NESTED EXCEPTION **
java.net.SocketException
MESSAGE: Software caused connection abort: recv failed
STACKTRACE:
java.net.SocketException: Software caused connection abort: recv failed
     at java.net.SocketInputStream.socketRead0(Native Method)
     at java.net.SocketInputStream.read(Unknown Source)
     at com.mysql.jdbc.util.ReadAheadInputStream.fill(ReadAheadInputStream.java:104)
     at com.mysql.jdbc.util.ReadAheadInputStream.readFromUnderlyingStreamIfNecessary(ReadAheadInputStream.java:144)
     at com.mysql.jdbc.util.ReadAheadInputStream.read(ReadAheadInputStream.java:172)
     at com.mysql.jdbc.MysqlIO.readFully(MysqlIO.java:1839)
     at com.mysql.jdbc.MysqlIO.reuseAndReadPacket(MysqlIO.java:2288)
     at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:2784)
     at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:1531)
     at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:1622)
     at com.mysql.jdbc.Connection.execSQL(Connection.java:2370)
     at com.mysql.jdbc.Connection.execSQL(Connection.java:2297)
     at com.mysql.jdbc.Statement.executeQuery(Statement.java:1183)
     at com.softnet.database.DatabaseController.executeDatabaseQuery(DatabaseController.java:190)
     at com.softnet.games.GameServer.validateUser(GameServer.java:438)
     at com.softnet.games.GameServer.handleData(GameServer.java:113)
     at com.softnet.network.HttpConnectionThread.run(HttpServletListener.java:191)
** END NESTED EXCEPTION **
I know the query is good because it works all other times just not after about 8 hours.
--Z3r0CooL                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               

Answer 1

Hey,
Thanks for the responces. For the connection pooling I would open 5 connections and keep them open. So i though maybe after 8 hours after not being used they would timeout. Thats why i turned off conection pooling and create a new connection each time. Anyways i'll post the code below incase i made a mistake somewhere.
package com.softnet.database;
/************************ DatabaseControler **************************/
import java.sql.*;
import java.util.*;
import com.softnet.database.DatabaseConnectionPool;
import com.softnet.database.DatabaseSettings;
public class DatabaseController
implements DatabaseListener
     //Used to make sure the database driver is loaded
     private boolean databaseDriverState = false;
     //Used to store a database connection
     private Connection databaseConnection = null;
     //If to user connection pooling or not
     private boolean useConnectionPooling = false;
     //Used to hold the connection pool varible
     private DatabaseConnectionPool connectionPool = null;
     //Used to store database settings
     private DatabaseSettings databaseSettings;
     //Used to hold the DatabaseController listeners
     private List databaseControllerListeners = new ArrayList();
     //min number of connections for connection pool
     private int minNumberOfConnections = 1;
     //max number of connections for connection pool -1 is unlimited
     private int maxNumberOfConnections = -1;
     //DatabaseController Constructors
     public DatabaseController(DatabaseSettings databaseSettings)
          this.databaseSettings = databaseSettings;
          databaseDriverState = loadDatabaseDriver(databaseSettings.getDatabaseDriver());
     public DatabaseController(DatabaseSettings databaseSettings, boolean useConnectionPooling, int minNumberOfConnections, int maxNumberOfConnections)
          this.databaseSettings = databaseSettings;
          this.useConnectionPooling = useConnectionPooling;
          this.minNumberOfConnections = minNumberOfConnections;
          this.maxNumberOfConnections = maxNumberOfConnections;
          if(useConnectionPooling == true)
               connectionPool = new DatabaseConnectionPool(databaseSettings, minNumberOfConnections, maxNumberOfConnections);
               connectionPool.addDatabaseListener(this);
          else
               databaseDriverState = loadDatabaseDriver(databaseSettings.getDatabaseDriver());
     public DatabaseController() {}
     //Database Settings Get/Set
     public DatabaseSettings getDatabaseSettings()
          return databaseSettings;
     public void setDatabaseSettings(DatabaseSettings databaseSettings)
          this.databaseSettings = databaseSettings;
     //Connection Pooling Get/Set
     public boolean getConnectionPooling()
          return useConnectionPooling;
     public void setConnectionPooling(boolean useConnectionPooling, int minNumberOfConnections, int maxNumberOfConnections)
          this.useConnectionPooling = useConnectionPooling;
          this.minNumberOfConnections = minNumberOfConnections;
          this.maxNumberOfConnections = maxNumberOfConnections;
          if(useConnectionPooling == true)
               if(connectionPool == null)
                    connectionPool = new DatabaseConnectionPool(databaseSettings, minNumberOfConnections, maxNumberOfConnections);
                    connectionPool.addDatabaseListener(this);
          else
               if(connectionPool != null)
                    connectionPool.destroyConnections();
                    connectionPool.removeDatabaseListener(this);
                    connectionPool = null;
     //Return if there connected
     public boolean isConnected()
          boolean isConnected;
          if(databaseConnection != null)
               isConnected = true;
          else
               isConnected = false;
          return isConnected;
     //Used to connect to database or get a connection for the connection pool
     public void connect()
          if(databaseDriverState == false)
               databaseDriverState = loadDatabaseDriver(databaseSettings.getDatabaseDriver());
          //If we dont have a current connection, make one
          if(databaseConnection == null && databaseDriverState == true)
               if(useConnectionPooling == false)
                    try
                         databaseConnection = DriverManager.getConnection(databaseSettings.getDatabaseURL(), databaseSettings.getUserName(), databaseSettings.getUserPassword());
                    catch (SQLException sqle)
                         //Raise event
                         raiseDatabaseEvent("DatabaseController: Error connecting to database. \nERROR: " + sqle.getMessage());
                         databaseConnection = null;
               else
                    databaseConnection = connectionPool.getConnection();
     //Used to disconnect from the database or give back the connection to the connection pool
     public void disconnect()
          if(databaseConnection != null)
               if(useConnectionPooling == false)
                    try
                         //Close DB Connection
                         databaseConnection.close();
                    catch(SQLException ignore) {}
                    finally
                         databaseConnection = null;
               else
                    connectionPool.returnConnection(databaseConnection);
                    databaseConnection = null;
     public ResultSet executeDatabaseQuery(String sSQL)
          ResultSet databaseResult = null;
          if(databaseConnection != null)
               try
                    Statement databaseStatement = databaseConnection.createStatement();
                    databaseResult = databaseStatement.executeQuery(sSQL);
               catch(SQLException sqle)
                    //Raise event
                    raiseDatabaseEvent("DatabaseController: Error executing database query.\nSQL: " + sSQL + "\nERROR: " + sqle.getMessage());
          return databaseResult;
     public int executeDatabaseUpdate(String sSQL)
          int rowsAffected = -1;
          if(databaseConnection != null)
               try
                    Statement databaseStatement = databaseConnection.createStatement();
                    rowsAffected = databaseStatement.executeUpdate(sSQL);
               catch(SQLException sqle)
                    //Raise event
                    raiseDatabaseEvent("DatabaseController: Error executing database update.\nSQL: " + sSQL + "\nERROR: " + sqle.getMessage());
          return rowsAffected;
     //Used to load the Database Driver
     private boolean loadDatabaseDriver(String databaseDriver)
          boolean driverLoaded;
          if(databaseDriver.equals("") == false)
               try
                    //Load Database Driver
                    Class.forName(databaseDriver).newInstance();
                    driverLoaded = true;
               catch (Exception e)
                    //Raise event
                    raiseDatabaseEvent("DatabaseController: Error loading database driver. \nERROR: " + e.getMessage());
                    driverLoaded = false;
          else
               driverLoaded = false;
          return driverLoaded;
     //Wrap the DatabaseConnectionPool Error to the DatabaseController
     public void databaseEventOccurred(DatabaseEvent de)
          raiseDatabaseEvent(de.getErrorMessage());
     //Event Handling Code
     //Used to add database listeners (Its sync'd so you can change the listeners when firing an event)
public synchronized void addDatabaseListener(DatabaseListener databaseControllerListener)
databaseControllerListeners.add(databaseControllerListener);
//Used to remove a listener from the list (Its sync'd so you can change the listeners when firing an event)
public synchronized void removeDatabaseListener(DatabaseListener databaseControllerListener)
databaseControllerListeners.remove(databaseControllerListener);
//Used to send the raise event to the listeners
private synchronized void raiseDatabaseEvent(String databaseError)
DatabaseEvent databaseEvent = new DatabaseEvent(this, databaseError);
Iterator listeners = databaseControllerListeners.iterator();
while(listeners.hasNext())
     DatabaseListener listener = (DatabaseListener) listeners.next();
listener.databaseEventOccurred(databaseEvent);
/********************* DatabaseConnectionPool **************/
package com.softnet.database;
import java.io.*;
import java.sql.*;
import java.util.*;
import com.softnet.database.*;
import com.softnet.database.DatabaseSettings;
public class DatabaseConnectionPool
     //min number of connections
     private int minNumberOfConnections = 1;
     //max number of connections -1 is unlimited
     private int maxNumberOfConnections = -1;
     //Store the connections
     protected Hashtable databaseConnections = null;
     //Database Info
     protected DatabaseSettings databaseSettings;
     //to hold Driver state
     private boolean databaseDriverState = false;
     //To hold connection checker
     private DatabaseConnectionCheck connectionChecker = null;
     //Used to hold the DatabaseConnectionPool listeners
     private List databaseConnectionPoolListeners = new ArrayList();
     public DatabaseConnectionPool(DatabaseSettings databaseSettings, int minNumberOfConnections, int maxNumberOfConnections)
          this.databaseSettings = databaseSettings;
          this.minNumberOfConnections = minNumberOfConnections;
          this.maxNumberOfConnections = maxNumberOfConnections;
          //Load Driver
          databaseDriverState = loadDatabaseDriver(databaseSettings.getDatabaseDriver());
          //Create connection
          createConnections();
     public DatabaseConnectionPool(int minNumberOfConnections, int maxNumberOfConnections)
          this.minNumberOfConnections = minNumberOfConnections;
          this.maxNumberOfConnections = maxNumberOfConnections;
     //Database Settings Get/Set
     public DatabaseSettings getDatabaseSettings()
          return databaseSettings;
     public void setDatabaseSettings(DatabaseSettings databaseSettings)
          this.databaseSettings = databaseSettings;
     //Driver State Get
     public boolean getDatabaseDriverState()
          return databaseDriverState;
     public void createConnections()
          if(databaseDriverState == false)
               databaseDriverState = loadDatabaseDriver(databaseSettings.getDatabaseDriver());
          //Create all connections and load the minimum in the Hashtable
          if(databaseConnections == null)
               if(databaseDriverState == true && minNumberOfConnections != 0)
                    databaseConnections = new Hashtable();
                    for(int i = 0; i < minNumberOfConnections; i++)
                         try
                              databaseConnections.put(DriverManager.getConnection(databaseSettings.getDatabaseURL(), databaseSettings.getUserName(), databaseSettings.getUserPassword()), Boolean.FALSE);
                         catch(SQLException sqle)
                              //Problem break loop and destroy any connections
                              destroyConnections();
                              //Raise event
                              raiseDatabaseEvent("DatabaseConnectionPool: Error creating database connections. \nERROR: " + sqle.getMessage());
                              break;
          //If no connection check exists create one
          if(connectionChecker == null)
               connectionChecker = new DatabaseConnectionCheck(this);
               connectionChecker.start();
     public Connection getConnection()
          Connection connection = null;
          boolean errorWithConnection = false;
          Enumeration connections = databaseConnections.keys();
          synchronized (databaseConnections)
               while(connections.hasMoreElements())
                    errorWithConnection = false;
                    connection = (Connection) connections.nextElement();
                    Boolean state = (Boolean) databaseConnections.get(connection);
                    //If connection is not used, use it.
                    if(state == Boolean.FALSE)
                         try
                              connection.setAutoCommit(true);
                         catch(SQLException e)
                              //Problem with connection remove connection and replace it
                              databaseConnections.remove(connection);
                              try
                                   connection = DriverManager.getConnection(databaseSettings.getDatabaseURL(), databaseSettings.getUserName(), databaseSettings.getUserPassword());
                              catch(SQLException sqle)
                                   errorWithConnection = true;
                         if(errorWithConnection == false)
                              // Update the Hashtable to show this one's taken
                              databaseConnections.put(connection, Boolean.TRUE);
                              // Return the connection
                              return connection;
               //All connections being used check to max to see if we can make a new one
               if(maxNumberOfConnections == -1 || maxNumberOfConnections > databaseConnections.size())
                    try
                         connection = DriverManager.getConnection(databaseSettings.getDatabaseURL(), databaseSettings.getUserName(), databaseSettings.getUserPassword());
                    catch(SQLException sqle)
                         errorWithConnection = true;
                    if(errorWithConnection == false)
                         databaseConnections.put(connection, Boolean.TRUE);
                         return connection;
          //If not connections free and max connections reached wait for a free connection
          return getConnection();
     public void returnConnection(Connection connection)
          boolean errorWithConnection = false;
          //Make sure connection still works
          try
               connection.setAutoCommit(true);
          catch(SQLException e)
               //Problem with connection remove connection and replace it
               databaseConnections.remove(connection);
               try
                    connection = DriverManager.getConnection(databaseSettings.getDatabaseURL(), databaseSettings.getUserName(), databaseSettings.getUserPassword());
               catch(SQLException sqle)
                    errorWithConnection = true;     
          if(errorWithConnection == false)
               databaseConnections.put(connection, Boolean.FALSE);
     public void destroyConnections()
          Connection connection = null;
          if(databaseConnections != null)
               //Close all connections
               Enumeration connections = databaseConnections.keys();
               while (connections.hasMoreElements())
                    connection = (Connection) connections.nextElement();
                    try
                         connection.close();
                    catch(SQLException ignore) {}
               //Free up hashtable
               databaseConnections = null;
     private boolean loadDatabaseDriver(String databaseDriver)
          boolean driverLoaded;
          if(databaseDriver.equals("") == false)
               try
                    //Load Database Driver
                    Class.forName(databaseDriver);
                    driverLoaded = true;
               catch (ClassNotFoundException cnfe)
                    //Raise event
                    raiseDatabaseEvent("DatabaseController: Error loading database driver. \nERROR: " + cnfe.getMessage());
                    driverLoaded = false;
          else
               driverLoaded = false;
          return driverLoaded;
     //Event Handling Code
     //Used to add database listeners (Its sync'd so you can change the listeners when firing an event)
public synchronized void addDatabaseListener(DatabaseListener databaseConnectionPoolListener)
databaseConnectionPoolListeners.add(databaseConnectionPoolListener);
//Used to remove a listener from the list (Its sync'd so you can change the listeners when firing an event)
public synchronized void removeDatabaseListener(DatabaseListener databaseConnectionPoolListener)
databaseConnectionPoolListeners.remove(databaseConnectionPoolListener);
//Used to send the raise event to the listeners
private synchronized void raiseDatabaseEvent(String databaseError)
DatabaseEvent databaseEvent = new DatabaseEvent(this, databaseError);
Iterator listeners = databaseConnectionPoolListeners.iterator();
while(listeners.hasNext())
     DatabaseListener listener = (DatabaseListener) listeners.next();
listener.databaseEventOccurred(databaseEvent);
class DatabaseConnectionCheck extends Thread
     private DatabaseConnectionPool connectionPool;
     DatabaseConnectionCheck(DatabaseConnectionPool connectionPool)
          this.connectionPool = connectionPool;
     public void run()
          try
               while(true)
                    //check threads every 30 seconds
                    this.sleep(300000);
                    if(connectionPool.databaseConnections != null)
                         Connection connection = null;
                         Enumeration connections = connectionPool.databaseConnections.keys();
                         synchronized (connectionPool.databaseConnections)
                              while(connections.hasMoreElements())
                                   connection = (Connection) connections.nextElement();
                                   Boolean state = (Boolean) connectionPool.databaseConnections.get(connection);
                                   //If connection is not used, use it.
                                   if(state == Boolean.FALSE)
                                        try
                                             connection.setAutoCommit(true);
                                        catch(SQLException e)
                                             //Problem with connection remove connection and replace it
                                             connectionPool.databaseConnections.remove(connection);
                                             try
                                                  connection = DriverManager.getConnection(connectionPool.databaseSettings.getDatabaseURL(), connectionPool.databaseSettings.getUserName(), connectionPool.databaseSettings.getUserPassword());
                                             catch(SQLException sqle)
                                                  connection = null;
                                             // Update the Hashtable with new connection if its not null
                                             if(connection != null)
                                                  connectionPool.databaseConnections.put(connection, Boolean.FALSE);
          catch(InterruptedException ignored) {}     
Basicly the why it works is the connection pool hold the database connections. When the user needs a connection they use the database controller to request a connection (By create a instance and called the connect() method) and the connection is either created or grabed from the connection pool. After the user is done with the connection they call the disconnect() method which closes the connection or returns it to the connection pool.
--Z3r0CooL