MySQL connection pooling (tomcat) problem

Hi all i just started learning servlets and i want to make a program in order to understand database connection pooling in tomcat.My problem is that when i run the servlet i created i get this error :
java.lang.NullPointerException org.DB.TestDB2.doGet(TestDB2.java:105) javax.servlet.http.HttpServlet.service(HttpServlet.java:690) javax.servlet.http.HttpServlet.service(HttpServlet.java:803) org.netbeans.modules.web.monitor.server.MonitorFilter.doFilter(MonitorFilter.java:390)
And that from tomcat log from netbeans :
org.apache.tomcat.dbcp.dbcp.SQLNestedException: Cannot create JDBC driver of class '' for connect URL 'null'
.I configured tomcat server.xml file like this :
<Context path="/DBTest" docBase="DBTest"         debug="5" reloadable="true" crossContext="true">   <Resource name="jdbc/phonebook_db" auth="Container" type="javax.sql.DataSource"               maxActive="100" maxIdle="30" maxWait="10000"               username="*******" password="********" removeAbandoned="true"               removeAbandonedTimeout="120" driverClassName="com.mysql.jdbc.Driver"               url="jdbc:mysql://localhost:3306/test_phonebook_db?autoReconnect=true"/> </Context>
This is the resource reference i have in my web app web.xml file :
<resource-ref>       <description>DB Connection</description>       <res-ref-name>jdbc/phonebook_db</res-ref-name>       <res-type>javax.sql.DataSource</res-type>       <res-auth>Container</res-auth>   </resource-ref>
And this is my servlet class :
package org.DB; import javax.servlet.*; import javax.servlet.http.*; import java.io.*; import java.sql.*; import javax.naming.*; import javax.sql.*; public class TestDB2 extends HttpServlet { private Connection conn ; private Statement stat ; private ResultSet rs ; private int counter; private Object rsValue; public void init() {     try {             InitialContext ctx = new InitialContext();             DataSource ds = (DataSource)ctx.lookup("java:comp/env/jdbc/phonebook_db");             conn = ds.getConnection();             }         catch(Exception e) {               e.printStackTrace();         }     }     public void doGet(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {         try {           stat = conn.createStatement();           rs = stat.executeQuery("SELECT * FROM phones_table");            } catch (SQLException sqle) {         sqle.printStackTrace();         }      response.setContentType("text/html; charset=utf-8");     PrintWriter out = response.getWriter();         String docType = "<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.0 " + "Transitional//EN\">\n";     out.println(docType +"<HTML>\n" + "<HEAD><TITLE>PhoneBook entries</TITLE></HEAD>\n");         counter = 0;     try {         while (rs.next()) {             out.println("<h4>Entry no. " + (++counter) + "</h4>");             out.println("<table width=\"75%\" border=\"1\">");             out.println("<tr>\n"+ "<td width=\21%\"><b>LastName:</b></td>\n"+ "<td width=\"79%\">");             out.println((((rsValue = rs.getObject("LASTNAME"))==null || rs.wasNull())?                 "":(rsValue.toString())));             out.println("</td>\n</tr>\n" + "<tr>\n"+                     "<td width=\21%\"><b>FirstName:</b></td>\n"+ "<td width=\"79%\">");             out.println((((rsValue = rs.getObject("FIRSTNAME"))==null || rs.wasNull())?                 "":(rsValue.toString())));             out.println("</td>\n"+ "</tr>\n"+                     "<td width=\21%\"><b>Phone:</b></td>\n"+ "<td width=\"79%\">");             out.println((((rsValue = rs.getObject("PHONE"))==null || rs.wasNull())?                 "":(rsValue.toString())));             out.println("</td>\n" + "</tr>\n" +                     "</table>\n"+ "<br>\n<br>");         }     } catch (SQLException sqle) {         sqle.printStackTrace();     }     out.println("</body>\n"+             "</html>"); } public void destroy() {     try {         rs.close();         stat.close();         conn.close();     } catch (SQLException sqle) {         sqle.printStackTrace();         }     } }{code} Any suggestions?

Thank you for your answer.Yes my servlet class is something more worse than horrible(i don't use the database connection correct i don't use the MVC pattern i use out.println() ) but i just tried to take a ready example and try to understand .So i write this servlet myself as a starting point :
package org.DB;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.*;
import java.sql.*;
public class DBServlet extends HttpServlet {
    private Connection conn ;
    private Statement stat ;
    private ResultSet rs ;
    private int counter;
    String driver = "com.mysql.jdbc.Driver";
    String dbURL = "jdbc:mysql://localhost:3306/phonebookdb?user=**********&password=************";
    @Override
public void init() {
     try {
            Class.forName(driver).newInstance();
            conn = DriverManager.getConnection(dbURL);
     }catch(Exception e) {
              e.printStackTrace();
              System.err.print("Unable to make connection ");
    protected void processRequest(HttpServletRequest request, HttpServletResponse response)
    throws ServletException, IOException {
        response.setContentType("text/html;charset=UTF-8");
        PrintWriter out = response.getWriter();
        try {
            out.println("<html>");
            out.println("<head>");
            out.println("<title>Servlet DBServlet</title>");
            out.println("</head>");
            out.println("<body>");
            out.println("<h1>Servlet DBServlet at " + request.getContextPath () + "</h1>");
            out.println("<br /><br /><br />");
            if(conn!=null)
                out.println("conn object : "+conn);
            out.println("</body>");
            out.println("</html>");
        } catch(Exception sq) {
            System.out.println("Exception" + sq.getMessage());
            out.close();
    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response)
    throws ServletException, IOException {
        processRequest(request, response);
    @Override
    protected void doPost(HttpServletRequest request, HttpServletResponse response)
    throws ServletException, IOException {
        processRequest(request, response);
     public void destroy() {
     try {
         conn.close();
     } catch (SQLException sqle) {
         sqle.printStackTrace();
    @Override
    public String getServletInfo() {
        return "A Simple Servlet";
}And it work for now.
Edited by: pavlos555 on Oct 21, 2008 10:21 AM

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** BEGIN NESTED EXCEPTION **
java.sql.SQLException
MESSAGE: Communication link failure: java.io.EOFException, underlying cause: null
** BEGIN NESTED EXCEPTION **
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** END NESTED EXCEPTION **
STACKTRACE:
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** BEGIN NESTED EXCEPTION **
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** END NESTED EXCEPTION **
     at com.mysql.jdbc.MysqlIO.reuseAndReadPacket(MysqlIO.java:1638)
     at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:1854)
     at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:1109)
     at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:1203)
     at com.mysql.jdbc.MysqlIO.sqlQuery(MysqlIO.java:1164)
     at com.mysql.jdbc.Connection.execSQL(Connection.java:2087)
     at com.mysql.jdbc.Connection.execSQL(Connection.java:2049)
     at com.mysql.jdbc.Connection.execSQL(Connection.java:2030)
     at com.mysql.jdbc.Connection.rollbackNoChecks(Connection.java:3004)
     at com.mysql.jdbc.Connection.rollback(Connection.java:1458)
     at com.sun.enterprise.resource.JdbcXAConnection$JdbcConnection.getCurrentConnection(JdbcXAConnection.java:640)
     at com.sun.enterprise.resource.JdbcXAConnection$JdbcConnection.prepareStatement(JdbcXAConnection.java:378)
     at net.sf.hibernate.impl.BatcherImpl.getPreparedStatement(BatcherImpl.java:228)
     at net.sf.hibernate.impl.BatcherImpl.prepareQueryStatement(BatcherImpl.java:61)
     at net.sf.hibernate.loader.Loader.prepareQueryStatement(Loader.java:703)
     at net.sf.hibernate.loader.Loader.doQuery(Loader.java:184)
     at net.sf.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:132)
     at net.sf.hibernate.loader.Loader.doList(Loader.java:949)
     at net.sf.hibernate.loader.Loader.list(Loader.java:940)
     at net.sf.hibernate.hql.QueryTranslator.list(QueryTranslator.java:833)
     at net.sf.hibernate.impl.SessionImpl.find(SessionImpl.java:1475)
     at net.sf.hibernate.impl.QueryImpl.list(QueryImpl.java:39)
     at jasper.monthly_jsp._jspService(_monthly_jsp.java:158)
     at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:107)
     at javax.servlet.http.HttpServlet.service(HttpServlet.java:853)
     at com.iplanet.ias.web.jsp.JspServlet$JspServletWrapper.service(JspServlet.java:552)
     at com.iplanet.ias.web.jsp.JspServlet.serviceJspFile(JspServlet.java:368)
     at com.iplanet.ias.web.jsp.JspServlet.service(JspServlet.java:287)
     at javax.servlet.http.HttpServlet.service(HttpServlet.java:853)
     at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:247)
     at org.apache.catalina.core.ApplicationFilterChain.access$000(ApplicationFilterChain.java:98)
     at org.apache.catalina.core.ApplicationFilterChain$1.run(ApplicationFilterChain.java:176)
     at java.security.AccessController.doPrivileged(Native Method)
     at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:172)
     at gr.netsmart.manos2.jstats.filters.WebStatisticsKeeper.doFilter(Unknown Source)
     at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:213)
     at org.apache.catalina.core.ApplicationFilterChain.access$000(ApplicationFilterChain.java:98)
     at org.apache.catalina.core.ApplicationFilterChain$1.run(ApplicationFilterChain.java:176)
     at java.security.AccessController.doPrivileged(Native Method)
     at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:172)
     at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:265)
     at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:505)
     at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:212)
     at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:505)
     at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:203)
     at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:505)
     at com.iplanet.ias.web.connector.nsapi.NSAPIProcessor.process(NSAPIProcessor.java:157)
     at com.iplanet.ias.web.WebContainer.service(WebContainer.java:598)
** END NESTED EXCEPTION **
     at com.mysql.jdbc.Connection.checkClosed(Connection.java:2225)
     at com.mysql.jdbc.Connection.setAutoCommit(Connection.java:501)
     at com.sun.enterprise.resource.JdbcXAConnection$JdbcConnection.getCurrentConnection(JdbcXAConnection.java:641)
     at com.sun.enterprise.resource.JdbcXAConnection$JdbcConnection.prepareStatement(JdbcXAConnection.java:378)
     at net.sf.hibernate.impl.BatcherImpl.getPreparedStatement(BatcherImpl.java:228)
     at net.sf.hibernate.impl.BatcherImpl.prepareQueryStatement(BatcherImpl.java:61)
     at net.sf.hibernate.loader.Loader.prepareQueryStatement(Loader.java:703)
     at net.sf.hibernate.loader.Loader.doQuery(Loader.java:184)
     at net.sf.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:132)
     at net.sf.hibernate.loader.Loader.doList(Loader.java:949)
     at net.sf.hibernate.loader.Loader.list(Loader.java:940)
     at net.sf.hibernate.hql.QueryTranslator.list(QueryTranslator.java:833)
     at net.sf.hibernate.impl.SessionImpl.find(SessionImpl.java:1475)
     ... 27 more

Why would connection pooling cause problems with a trigger?

This is a strange one. We have an app that deletes a row in a database table, and this table has a delete trigger on it. The row gets deleted every time the app is run, yet the trigger only fires intermittently. It's not that the trigger is failiing in some way - it just doesn't get called at all. If I issue the same delete command in PL/SQL developer then the trigger fires every time.
Several hours later and out of desparation I tried turning off connection pooling via the app's connection string, and found that the trigger now fires every time. Any ideas what might be causing this behaviour? I can reproduce/fix the issue every time simply by setting "Pooling" to true or false!
We are using Oracle 11g and ODP.Net v4.112.2.0.
Thanks in advance
Andrew

More information: I've now been able to reproduce this issue in a small .Net app, and can make it fail in a more consistent manner (which I'll explain later). While it's still too large to post the entire code here, I can summarise what the app does in pseudo-code:-
for(int i = 1; i <= 10; i++) // Run the test a number of times
// Step 1 - Delete rows from the table with the delete query in question
Execute non-query "delete from test_table";
Wait 1 second
// Step 2 - Check that the delete actually happened
Execute reader "select count(*) from test_table"
Display the count
// Step 3 - Check that the delete trigger inserted some rows into a "logging" table. This is my method of "tracing" - I added a basic insert to the start of each trigger section, as mentioned in my previous post.
Execute reader "select count(*) from my_logging_table"
Display the count
// Reinstate the test data
Execute non-query "<insert rows back into test_table>"
Wait 1 second
For info the connection string is fairly basic:- "Data Source=<tns name>;User Id=<foo>;Password=<bar>"
Some points of interest:-
- When running the above test app, the trigger successfully fires on the very first iteration (i.e. "Step 3" displays a non-zero count from the logging table). All subsequent iterations fail ("Step 3" displays the same count each time).
- If I turn off connection pooling (by adding "Pooling=false" to the connection string), the trigger runs on every iteration (i.e. "Step 3" displays an ever-incrementing record count).
- Regardless of whether it works or fails, the deletion in step 1 does take place (confirmed by "Step 2" displaying a count of zero).
- I added the waits after the non-query calls to see if that made a difference, but it doesn't. I can change these to 10 seconds or more and it will have no effect on the issue.
The "Execute non-query" method uses code along these lines:-
using (var conn = new OracleConnection(ConnString))
conn.Open();
using (var cmd = conn.CreateCommand())
cmd.CommandText = sql;
cmd.CommandType = CommandType.Text;
result = cmd.ExecuteNonQuery();
conn.Close();
return result;
While the "Execute reader" method looks like this:-
var conn = new OracleConnection(ConnString);
conn.Open();
var cmd = conn.CreateCommand();
cmd.CommandText = sql;
cmd.CommandType = CommandType.Text;
return cmd.ExecuteReader(CommandBehavior.CloseConnection);
The calling code in the for loop, wraps the returned reader in a using clause like this:-
using (var reader = ExecuteReader("<sql>"))
This will dispose of the reader, which will in turn close/dispose the connection (due to the CommandBehavior.CloseConnection parameter passed to ExecuteReader).
Interestingly, if the reader isn't disposed of then the problem becomes more intermittent (the trigger will fire perhaps 25% of the time). This is what's happening in our unit test harness. By ensuring the reader/connection is closed and disposed (which common sense would say should improve matters), the trigger only fires on the very first iteration of the loop. The plot thickens.

Connection Pool establishment problem

Hi Experts,
we have one application with JCo mechanism. For this application,
we are using one properties file, which holds ABAP connection information. From this connection information(sapconn.props), we created connection pool and fetching data from the back end. Now my requirement is, instead of this properties file, we want to use one SLD, from this i would like to fetch connection information and establish a connection pool. How can we implement this one...?
Is there any API to read the ABAP connection informaation from visual admin (JCo RFC provider) ?
Thanks
maha

Your question has been answered in this [thread|connection establishment doubt;.
Please read the [rules|https://wiki.sdn.sap.com/wiki/display/HOME/RulesofEngagement], in particular - do not cross post.
-- Vladimir

Toplink Mysql Connection pool issues

I am frequently seeing threads in wait state on toplink connection pool, I have given the stack trace below, anyone has any ideas as to what is happening? is it
related to connection timeout? or other causes...
"http-0.0.0.0-8080-2" id=397 idx=0x620 tid=5344 prio=5 alive, in native, waiting
, daemon
-- Waiting for notification on: oracle/toplink/threetier/ConnectionPool@0x00
F181D8[fat lock]
at jrockit/vm/Threads.waitForNotifySignal(JLjava/lang/Object;)Z(Native Metho
d)
at java/lang/Object.wait(J)V(Native Method)[optimized]
at java/lang/Object.wait(Object.java:474)
at oracle/toplink/threetier/ConnectionPool.acquireConnection(ConnectionPool.
java:65)
^-- Lock released while waiting: oracle/toplink/threetier/ConnectionPool@0x0
0F181D8[fat lock]
at oracle/toplink/threetier/ServerSession.allocateReadConnection(ServerSessi
on.java:412)
at oracle/toplink/threetier/ServerSession.executeCall(ServerSession.java:443
at oracle/toplink/internal/queryframework/DatasourceCallQueryMechanism.execu
teCall(DatasourceCallQueryMechanism.java:193)
at oracle/toplink/internal/queryframework/DatasourceCallQueryMechanism.execu
teCall(DatasourceCallQueryMechanism.java:179)
at oracle/toplink/internal/queryframework/DatasourceCallQueryMechanism.execu
teSelectCall(DatasourceCallQueryMechanism.java:250)
at oracle/toplink/internal/queryframework/DatasourceCallQueryMechanism.selec
tAllRows(DatasourceCallQueryMechanism.java:583)
at oracle/toplink/internal/queryframework/ExpressionQueryMechanism.selectAll
RowsFromTable(ExpressionQueryMechanism.java:2483)
at oracle/toplink/internal/queryframework/ExpressionQueryMechanism.selectAll
Rows(ExpressionQueryMechanism.java:2441)
at oracle/toplink/queryframework/ReadAllQuery.executeObjectLevelReadQuery(Re
adAllQuery.java:467)
at oracle/toplink/queryframework/ObjectLevelReadQuery.executeDatabaseQuery(O
bjectLevelReadQuery.java:874)
at oracle/toplink/queryframework/DatabaseQuery.execute(DatabaseQuery.java:67
4)
at oracle/toplink/queryframework/ObjectLevelReadQuery.execute(ObjectLevelRea
dQuery.java:835)
at oracle/toplink/queryframework/ReadAllQuery.execute(ReadAllQuery.java:445)
at oracle/toplink/internal/sessions/AbstractSession.internalExecuteQuery(Abs
tractSession.java:2260)
at oracle/toplink/internal/sessions/AbstractSession.executeQuery(AbstractSes
sion.java:1074)
at oracle/toplink/internal/sessions/AbstractSession.executeQuery(AbstractSes
sion.java:1058)
at oracle/toplink/internal/sessions/AbstractSession.executeQuery(AbstractSes
sion.java:1017)
at com/integral/query/QueryServiceC.executeQuery(QueryServiceC.java:1030)
at com/integral/query/QueryServiceC._find(QueryServiceC.java:525)
at com/integral/query/QueryServiceC._findAll(QueryServiceC.java:123)
at com/integral/query/QueryServiceC.findAll(QueryServiceC.java:83)
at com/integral/query/ejb/QueryServiceC.findAll(QueryServiceC.java:59)

Hello,
It looks like you are using a TopLink managed connection pool and do not have enough connections available for the number of threads needing to use one. This results in threads having to wait until one is released from another thread. In the thread shown, it is waiting to get a read connection from the read pool.
TopLink connection pools are described in the docs at:
http://www.oracle.com/technology/products/ias/toplink/doc/1013/main/_html/srvclius002.htm#CHDJAECD
I'd recommend increasing the min/max number of connections to something that is appropriate to handle your peak load based on your applications usage paterns.
Best Regards,
Chris

MySql connection pooling in Tomcat 4.1

Hi,
Could somebody help me before I go insane ?
I have installed Tomcat 4.1 and MySql and is now trying to follow the example at http://jakarta.apache.org/tomcat/tomcat-4.1-doc/jndi-datasource-examples-howto.html to set up a pooled connection to the database.
When i try to look up the DataSource :
DataSource ds = (DataSource) initCtx.lookup("java:comp/env/jdbc/lonDB");
I get an error :
DbcpDataSourceFactory: driverClassName is required
cheers
/H

Hello,
Even though my problem is different, I just appended to this older posting because I am following the same tutorial for setting up a DB Conn pool with MySql.
The problem that I am having is that Tomcat can't find the DBTest class which I copied and compiled from the tutorial.
Where does one have to place their classes for Tomcat 4.1 to see them? In the older version of Tomcat which we use, all we had to was to place the class directory in the CLASSPATH variable on the server, and Tomcat was able to access the classes. We did the same approach for v4.1 but it does not seem to be working.
Any help is appreciated!
Thanks,
Chris

Serious problem of jdbc-mysql connectivity using tomcat

hi everybody
i m in serious problem since last 15-20 days. i m trying hard to make the connection jdbc-mysql using tomcat with the help of a jsp test page but every time i am facing almost the similar probems listed below in detail:
to make sure that the jdrivers's .jar (mysql-connector-java-3.1.7-bin.jar) available for such connections working fine i have tried the above said connection without using tomcat....which is working fine...for this i have created a dummy database with a dummy table ..and written some queries in the .java file of my code which upon running inserts the specified values in the defined(dummy) database.
this is the confirmation that the classpath etc..are ok in regard to the mysql-connector-java-3.1.7-bin.jar
now i have placed a copy of this .jar file in to the commons/lib directory of the tomcat web server(which is suppossed to be the place for such external jars)
after doing so i have followed 2 methods :
method 1st:........
i have made aone more jar file from the following .java file....
import javax.naming.*;
import javax.sql.*;
import java.sql.*;
public class TestSQLLoad
String user = "Not Connected";
String pwd = "no pwd";
int id = -1;
public void init() {
try{
Context ctx = new InitialContext();
if(ctx == null ) {
throw new Exception("Boom - No Context");
DataSource ds = (DataSource)ctx.lookup("java:comp/env/jdbc/TestDB");
if (ds != null) {
Connection conn = ds.getConnection();
if(conn != null) {
user = "Got Connection "+conn.toString();
Statement stmt = conn.createStatement();
String q = "select name, password, id from user";
ResultSet rst = stmt.executeQuery(q);
if(rst.next()) {
user=rst.getString(1);
pwd=rst.getString(2);
id = rst.getInt(3);
conn.close();
}catch(Exception e) {
e.printStackTrace();
public String getUser() {
return user;
public String getPassword() {
return pwd;
public int getID()
return id;
after compiling it at the cmd prompt i made a .jar file from the .class of it and named it MySQLLoad.jar...then i placed it also in to the commons/lib directory where the mysql-connector-java-3.1.7-bin.jar was already placed.
then i have changed the server.xml and web.xml files from the conf directory of the tomcat as given here:
server.xml



<Server port="8005" shutdown="SHUTDOWN">

<Listener className="org.apache.catalina.mbeans.ServerLifecycleListener" />
<Listener className="org.apache.catalina.mbeans.GlobalResourcesLifecycleListener" />

<GlobalNamingResources>

<Environment name="simpleValue" type="java.lang.Integer" value="30"/>

<Resource name="UserDatabase" auth="Container"
type="org.apache.catalina.UserDatabase"
description="User database that can be updated and saved"
factory="org.apache.catalina.users.MemoryUserDatabaseFactory"
pathname="conf/tomcat-users.xml" />
</GlobalNamingResources>


<Service name="Catalina">

<Connector
port="80" maxThreads="150" minSpareThreads="25" maxSpareThreads="75"
enableLookups="false" redirectPort="8443" acceptCount="100"
connectionTimeout="20000" disableUploadTimeout="true" />


<Connector port="8009"
enableLookups="false" redirectPort="8443" protocol="AJP/1.3" />

<Engine name="Catalina" defaultHost="localhost">
<Realm className="org.apache.catalina.realm.UserDatabaseRealm"
resourceName="UserDatabase"/>
<Host name="localhost" appBase="webapps"
unpackWARs="true" autoDeploy="true"
xmlValidation="false" xmlNamespaceAware="false">
<Context path="/testdb" docBase="TOMCAT_HOME/webapps/tomcat-docs/testdb"
debug="5" reloadable="true" crossContext="true" >
<Logger className="org.apache.catalina.logger.FileLogger"
prefix="localhost_DBTest_log." suffix=".txt"
timestamp="true"/>
<Resource name="jdbc/TestDB"
auth="Container"
type="javax.sql.DataSource"/>
<ResourceParams name="jdbc/TestDB">
<parameter>
<name>factory</name>
<value>org.apache.commons.dbcp.BasicDataSourceFactory</value>
</parameter>
<parameter>
<name>maxActive</name>
<value>10</value>
</parameter>
<parameter>
<name>maxIdle</name>
<value>5</value>
</parameter>
<parameter>
<name>maxWait</name>
<value>10000</value>
</parameter>

<parameter>
<name>username</name>
<value>root</value>
</parameter>
<parameter>
<name>password</name>
<value>mysql</value>
</parameter>

<parameter>
<name>driverClassName</name>
<value>com.mysql.jdbc.Driver</value>
</parameter>
<parameter>
<name>url</name>
<value>jdbc:mysql://localhost/testdb?autoReconnect=true</value>
</parameter>
</ResourceParams>
</Context>
</Host>
</Engine>
</Service>
</Server>
and the other xml file i.e
web.xml is here:
<?xml version="1.0" encoding="ISO-8859-1"?>
<web-app xmlns="http://java.sun.com/xml/ns/j2ee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd"
version="2.4">
<servlet>
<servlet-name>default</servlet-name>
<resource-ref>
<description>DB Connection</description>
<res-ref-name>jdbc/TestDB</res-ref-name>
<res-type>javax.sql.DataSource</res-type>
<res-auth>Container</res-auth>
</resource-ref>
<servlet-class>org.apache.catalina.servlets.DefaultServlet</servlet-cl ***>
<init-param>
<param-name>debug</param-name>
<param-value>0</param-value>
</init-param>
<init-param>
<param-name>listings</param-name>
<param-value>true</param-value>
</init-param>
<load-on-startup>1</load-on-startup>
</servlet>
<servlet>
<servlet-name>invoker</servlet-name>
<servlet-class>
org.apache.catalina.servlets.InvokerServlet
</servlet-class>
<init-param>
<param-name>debug</param-name>
<param-value>0</param-value>
</init-param>
<load-on-startup>2</load-on-startup>
</servlet>
<servlet>
<servlet-name>jsp</servlet-name>
<servlet-class>org.apache.jasper.servlet.JspServlet</servlet-class>
<init-param>
<param-name>fork</param-name>
<param-value>false</param-value>
</init-param>
<init-param>
<param-name>xpoweredBy</param-name>
<param-value>false</param-value>
</init-param>
<load-on-startup>3</load-on-startup>
</servlet>
<servlet-mapping>
<servlet-name>invoker</servlet-name>
<url-pattern>/servlet/*</url-pattern>
</servlet-mapping>

<servlet-mapping>
<servlet-name>jsp</servlet-name>
<url-pattern>*.jsp</url-pattern>
</servlet-mapping>
<servlet-mapping>
<servlet-name>jsp</servlet-name>
<url-pattern>*.jspx</url-pattern>
</servlet-mapping>
<session-config>
<session-timeout>30</session-timeout>
</session-config>
<mime-mapping>
<extension>abs</extension>
<mime-type>audio/x-mpeg</mime-type>
</mime-mapping>
<mime-mapping>
<extension>ai</extension>
<mime-type>application/postscript</mime-type>
</mime-mapping>
<mime-mapping>
<extension>aif</extension>
<mime-type>audio/x-aiff</mime-type>
</mime-mapping>
<mime-mapping>
<extension>aifc</extension>
<mime-type>audio/x-aiff</mime-type>
</mime-mapping>
<mime-mapping>
<extension>aiff</extension>
<mime-type>audio/x-aiff</mime-type>
</mime-mapping>
<mime-mapping>
<extension>aim</extension>
<mime-type>application/x-aim</mime-type>
</mime-mapping>
<mime-mapping>
<extension>art</extension>
<mime-type>image/x-jg</mime-type>
</mime-mapping>
<mime-mapping>
<extension>asf</extension>
<mime-type>video/x-ms-asf</mime-type>
</mime-mapping>
<mime-mapping>
<extension>asx</extension>
<mime-type>video/x-ms-asf</mime-type>
</mime-mapping>
<mime-mapping>
<extension>au</extension>
<mime-type>audio/basic</mime-type>
</mime-mapping>
<mime-mapping>
<extension>avi</extension>
<mime-type>video/x-msvideo</mime-type>
</mime-mapping>
<mime-mapping>
<extension>avx</extension>
<mime-type>video/x-rad-screenplay</mime-type>
</mime-mapping>
<mime-mapping>
<extension>bcpio</extension>
<mime-type>application/x-bcpio</mime-type>
</mime-mapping>
<mime-mapping>
<extension>bin</extension>
<mime-type>application/octet-stream</mime-type>
</mime-mapping>
<mime-mapping>
<extension>bmp</extension>
<mime-type>image/bmp</mime-type>
</mime-mapping>
<mime-mapping>
<extension>body</extension>
<mime-type>text/html</mime-type>
</mime-mapping>
<mime-mapping>
<extension>cdf</extension>
<mime-type>application/x-cdf</mime-type>
</mime-mapping>
<mime-mapping>
<extension>cer</extension>
<mime-type>application/x-x509-ca-cert</mime-type>
</mime-mapping>
<mime-mapping>
<extension>class</extension>
<mime-type>application/java</mime-type>
</mime-mapping>
<mime-mapping>
<extension>cpio</extension>
<mime-type>application/x-cpio</mime-type>
</mime-mapping>
<mime-mapping>
<extension>csh</extension>
<mime-type>application/x-csh</mime-type>
</mime-mapping>
<mime-mapping>
<extension>css</extension>
<mime-type>text/css</mime-type>
</mime-mapping>
<mime-mapping>
<extension>dib</extension>
<mime-type>image/bmp</mime-type>
</mime-mapping>
<mime-mapping>
<extension>doc</extension>
<mime-type>application/msword</mime-type>
</mime-mapping>
<mime-mapping>
<extension>dtd</extension>
<mime-type>text/plain</mime-type>
</mime-mapping>
<mime-mapping>
<extension>dv</extension>
<mime-type>video/x-dv</mime-type>
</mime-mapping>
<mime-mapping>
<extension>dvi</extension>
<mime-type>application/x-dvi</mime-type>
</mime-mapping>
<mime-mapping>
<extension>eps</extension>
<mime-type>application/postscript</mime-type>
</mime-mapping>
<mime-mapping>
<extension>etx</extension>
<mime-type>text/x-setext</mime-type>
</mime-mapping>
<mime-mapping>
<extension>exe</extension>
<mime-type>application/octet-stream</mime-type>
</mime-mapping>
<mime-mapping>
<extension>gif</extension>
<mime-type>image/gif</mime-type>
</mime-mapping>
<mime-mapping>
<extension>gtar</extension>
<mime-type>application/x-gtar</mime-type>
</mime-mapping>
<mime-mapping>
<extension>gz</extension>
<mime-type>application/x-gzip</mime-type>
</mime-mapping>
<mime-mapping>
<extension>hdf</extension>
<mime-type>application/x-hdf</mime-type>
</mime-mapping>
<mime-mapping>
<extension>hqx</extension>
<mime-type>application/mac-binhex40</mime-type>
</mime-mapping>
<mime-mapping>
<extension>htc</extension>
<mime-type>text/x-component</mime-type>
</mime-mapping>
<mime-mapping>
<extension>htm</extension>
<mime-type>text/html</mime-type>
</mime-mapping>
<mime-mapping>
<extension>html</extension>
<mime-type>text/html</mime-type>
</mime-mapping>
<mime-mapping>
<extension>hqx</extension>
<mime-type>application/mac-binhex40</mime-type>
</mime-mapping>
<mime-mapping>
<extension>ief</extension>
<mime-type>image/ief</mime-type>
</mime-mapping>
<mime-mapping>
<extension>jad</extension>
<mime-type>text/vnd.sun.j2me.app-descriptor</mime-type>
</mime-mapping>
<mime-mapping>
<extension>jar</extension>
<mime-type>application/java-archive</mime-type>
</mime-mapping>
<mime-mapping>
<extension>java</extension>
<mime-type>text/plain</mime-type>
</mime-mapping>
<mime-mapping>
<extension>jnlp</extension>
<mime-type>application/x-java-jnlp-file</mime-type>
</mime-mapping>
<mime-mapping>
<extension>jpe</extension>
<mime-type>image/jpeg</mime-type>
</mime-mapping>
<mime-mapping>
<extension>jpeg</extension>
<mime-type>image/jpeg</mime-type>
</mime-mapping>
<mime-mapping>
<extension>jpg</extension>
<mime-type>image/jpeg</mime-type>
</mime-mapping>
<mime-mapping>
<extension>js</extension>
<mime-type>text/javascript</mime-type>
</mime-mapping>
<mime-mapping>
<extension>jsf</extension>
<mime-type>text/plain</mime-type>
</mime-mapping>
<mime-mapping>
<extension>jspf</extension>
<mime-type>text/plain</mime-type>
</mime-mapping>
<mime-mapping>
<extension>kar</extension>
<mime-type>audio/x-midi</mime-type>
</mime-mapping>
<mime-mapping>
<extension>latex</extension>
<mime-type>application/x-latex</mime-type>
</mime-mapping>
<mime-mapping>
<extension>m3u</extension>
<mime-type>audio/x-mpegurl</mime-type>
</mime-mapping>
<mime-mapping>
<extension>mac</extension>
<mime-type>image/x-macpaint</mime-type>
</mime-mapping>
<mime-mapping>
<extension>man</extension>
<mime-type>application/x-troff-man</mime-type>
</mime-mapping>
<mime-mapping>
<extension>me</extension>
<mime-type>application/x-troff-me</mime-type>
</mime-mapping>
<mime-mapping>
<extension>mid</extension>
<mime-type>audio/x-midi</mime-type>
</mime-mapping>
<mime-mapping>
<extension>midi</extension>
<mime-type>audio/x-midi</mime-type>
</mime-mapping>
<mime-mapping>
<extension>mif</extension>
<mime-type>application/x-mif</mime-type>
</mime-mapping>
<mime-mapping>
<extension>mov</extension>
<mime-type>video/quicktime</mime-type>
</mime-mapping>
<mime-mapping>
<extension>movie</extension>
<mime-type>video/x-sgi-movie</mime-type>
</mime-mapping>
<mime-mapping>
<extension>mp1</extension>
<mime-type>audio/x-mpeg</mime-type>
</mime-mapping>
<mime-mapping>
<extension>mp2</extension>
<mime-type>audio/x-mpeg</mime-type>
</mime-mapping>
<mime-mapping>
<extension>mp3</extension>
<mime-type>audio/x-mpeg</mime-type>
</mime-mapping>
<mime-mapping>
<extension>mpa</extension>
<mime-type>audio/x-mpeg</mime-type>
</mime-mapping>
<mime-mapping>
<extension>mpe</extension>
<mime-type>video/mpeg</mime-type>
</mime-mapping>
<mime-mapping>
<extension>mpeg</extension>
<mime-type>video/mpeg</mime-type>
</mime-mapping>
<mime-mapping>
<extension>mpega</extension>
<mime-type>audio/x-mpeg</mime-type>
</mime-mapping>
<mime-mapping>
<extension>mpg</extension>
<mime-type>video/mpeg</mime-type>
</mime-mapping>
<mime-mapping>
<extension>mpv2</extension>
<mime-type>video/mpeg2</mime-type>
</mime-mapping>
<mime-mapping>
<extension>ms</extension>
<mime-type>application/x-wais-source</mime-type>
</mime-mapping>
<mime-mapping>
<extension>nc</extension>
<mime-type>application/x-netcdf</mime-type>
</mime-mapping>
<mime-mapping>
<extension>oda</extension>
<mime-type>application/oda</mime-type>
</mime-mapping>
<mime-mapping>
<extension>pbm</extension>
<mime-type>image/x-portable-bitmap</mime-type>
</mime-mapping>
<mime-mapping>
<extension>pct</extension>
<mime-type>image/pict</mime-type>
</mime-mapping>
<mime-mapping>
<extension>pdf</extension>
<mime-type>application/pdf</mime-type>
</mime-mapping>
<mime-mapping>
<extension>pgm</extension>
<mime-type>image/x-portable-graymap</mime-type>
</mime-mapping>
<mime-mapping>
<extension>pic</extension>
<mime-type>image/pict</mime-type>
</mime-mapping>
<mime-mapping>
<extension>pict</extension>
<mime-type>image/pict</mime-type>
</mime-mapping>
<mime-mapping>
<extension>pls</extension>
<mime-type>audio/x-scpls</mime-type>
</mime-mapping>
<mime-mapping>
<extension>png</extension>
<mime-type>image/png</mime-type>
</mime-mapping>
<mime-mapping>
<extension>pnm</extension>
<mime-type>image/x-portable-anymap</mime-type>
</mime-mapping>
<mime-mapping>
<extension>pnt</extension>
<mime-type>image/x-macpaint</mime-type>
</mime-mapping>
<mime-mapping>
<extension>ppm</extension>
<mime-type>image/x-portable-pixmap</mime-type>
</mime-mapping>
<mime-mapping>
<extension>ppt</extension>
<mime-type>application/powerpoint</mime-type>
</mime-mapping>
<mime-mapping>
<extension>ps</extension>
<mime-type>application/postscript</mime-type>
</mime-mapping>
<mime-mapping>
<extension>psd</extension>
<mime-type>image/x-photoshop</mime-type>
</mime-mapping>
<mime-mapping>
<extension>qt</extension>
<mime-type>video/quicktime</mime-type>
</mime-mapping>
<mime-mapping>
<extension>qti</extension>
<mime-type>image/x-quicktime</mime-type>
</mime-mapping>
<mime-mapping>
<extension>qtif</extension>
<mime-type>image/x-quicktime</mime-type>
</mime-mapping>
<mime-mapping>
<extension>ras</extension>
<mime-type>image/x-cmu-raster</mime-type>
</mime-mapping>
<mime-mapping>
<extension>rgb</extension>
<mime-type>image/x-rgb</mime-type>
</mime-mapping>
<mime-mapping>
<extension>rm</extension>
<mime-type>application/vnd.rn-realmedia</mime-type>
</mime-mapping>
<mime-mapping>
<extension>roff</extension>
<mime-type>application/x-troff</mime-type>
</mime-mapping>
<mime-mapping>
<extension>rtf</extension>
<mime-type>application/rtf</mime-type>
</mime-mapping>
<mime-mapping>
<extension>rtx</extension>
<mime-type>text/richtext</mime-type>
</mime-mapping>
<mime-mapping>
<extension>sh</extension>
<mime-type>application/x-sh</mime-type>
</mime-mapping>
<mime-mapping>
<extension>shar</extension>
<mime-type>application/x-shar</mime-type>
</mime-mapping>
<mime-mapping>
<extension>smf</extension>
<mime-type>audio/x-midi</mime-type>
</mime-mapping>
<mime-mapping>
<extension>sit</extension>
<mime-type>application/x-stuffit</mime-type>
</mime-mapping>
<mime-mapping>
<extension>snd</extension>
<mime-type>audio/basic</mime-type>
</mime-mapping>
<mime-mapping>
<extension>src</extension>
<mime-type>application/x-wais-source</mime-type>
</mime-mapping>
<mime-mapping>
<extension>sv4cpio</extension>
<mime-type>application/x-sv4cpio</mime-type>
</mime-mapping>
<mime-mapping>
<extension>sv4crc</extension>
<mime-type>application/x-sv4crc</mime-type>
</mime-mapping>
<mime-mapping>
<extension>swf</extension>
<mime-type>application/x-shockwave-flash</mime-type>
</mime-mapping>
<mime-mapping>
<extension>t</extension>
<mime-type>application/x-troff</mime-type>
</mime-mapping>
<mime-mapping>
<extension>tar</extension>
<mime-type>application/x-tar</mime-type>
</mime-mapping>
<mime-mapping>
<extension>tcl</extension>
<mime-type>application/x-tcl</mime-type>
</mime-mapping>
<mime-mapping>
<extension>tex</extension>
<mime-type>application/x-tex</mime-type>
</mime-mapping>
<mime-mapping>
<extension>texi</extension>
<mime-type>application/x-texinfo</mime-type>
</mime-mapping>
<mime-mapping>
<extension>texinfo</extension>
<mime-type>application/x-texinfo</mime-type>
</mime-mapping>
<mime-mapping>
<extension>tif</extension>
<mime-type>image/tiff</mime-type>
</mime-mapping>
<mime-mapping>
<extension>tiff</extension>
<mime-type>image/tiff</mime-type>
</mime-mapping>
<mime-mapping>
<extension>tr</extension>
<mime-type>application/x-troff</mime-type>
</mime-mapping>
<mime-mapping>
<extension>tsv</extension>
<mime-type>text/tab-separated-values</mime-type>
</mime-mapping>
<mime-mapping>
<extension>txt</extension>
<mime-type>text/plain</mime-type>
</mime-mapping>
<mime-mapping>
<extension>ulw</extension>
<mime-type>audio/basic</mime-type>
</mime-mapping>
<mime-mapping>
<extension>ustar</extension>
<mime-type>application/x-ustar</mime-type>
</mime-mapping>
<mime-mapping>
<extension>xbm</extension>
<mime-type>image/x-xbitmap</mime-type>
</mime-mapping>
<mime-mapping>
<extension>xht</extension>
<mime-type>application/xhtml</mime-type>
</mime-mapping>
<mime-mapping>
<extension>xhtml</extension>
<mime-type>application/xhtml</mime-type>
</mime-mapping>
<mime-mapping>
<extension>xml</extension>
<mime-type>text/xml</mime-type>
</mime-mapping>
<mime-mapping>
<extension>xpm</extension>
<mime-type>image/x-xpixmap</mime-type>
</mime-mapping>
<mime-mapping>
<extension>xsl</extension>
<mime-type>text/xml</mime-type>
</mime-mapping>
<mime-mapping>
<extension>xwd</extension>
<mime-type>image/x-xwindowdump</mime-type>
</mime-mapping>
<mime-mapping>
<extension>wav</extension>
<mime-type>audio/x-wav</mime-type>
</mime-mapping>
<mime-mapping>
<extension>svg</extension>
<mime-type>image/svg</mime-type>
</mime-mapping>
<mime-mapping>
<extension>svgz</extension>
<mime-type>image/svg</mime-type>
</mime-mapping>
<mime-mapping>
<extension>vsd</extension>
<mime-type>application/x-visio</mime-type>
</mime-mapping>
<mime-mapping>

<extension>wbmp</extension>
<mime-type>image/vnd.wap.wbmp</mime-type>
</mime-mapping>
<mime-mapping>

<extension>wml</extension>
<mime-type>text/vnd.wap.wml</mime-type>
</mime-mapping>
<mime-mapping>

<extension>wmlc</extension>
<mime-type>application/vnd.wap.wmlc</mime-type>
</mime-mapping>
<mime-mapping>

<extension>wmls</extension>
<mime-type>text/vnd.wap.wmlscript</mime-type>
</mime-mapping>
<mime-mapping>

<extension>wmlscriptc</extension>
<mime-type>application/vnd.wap.wmlscriptc</mime-type>
</mime-mapping>
<mime-mapping>
<extension>wrl</extension>
<mime-type>x-world/x-vrml</mime-type>
</mime-mapping>
<mime-mapping>
<extension>Z</extension>
<mime-type>application/x-compress</mime-type>
</mime-mapping>
<mime-mapping>
<extension>z</extension>
<mime-type>application/x-compress</mime-type>
</mime-mapping>
<mime-mapping>
<extension>zip</extension>
<mime-type>application/zip</mime-type>
</mime-mapping>
<welcome-file-list>
<welcome-file>index.html</welcome-file>
<welcome-file>index.htm</welcome-file>
<welcome-file>index.jsp</welcome-file>
</welcome-file-list>
</web-app>
after all this i have taken a jsp page whose code is here:
(the mysql database used is named as "testdb" and the table name is "user" which is having fields name,password and id)
<html>
<head>
<title>DB Test</title>
</head>
<body>
<%
TestSQLLoad tst = new TestSQLLoad ( );
tst.init();
%>
<h2>Results</h2>
User <%= tst.getUser() %>
Pwd <%= tst.getPassword() %>
Id <%= tst.getID() %>
</body>
</html>
and placed it in to the Tomcat 5.5\webapps\tomcat-docs\testdb directory and saved as test-db.jsp
when i run this page on the browser i get a lot may errors stating
org.apache.jasper.JasperException: Unable to compile class for JSP
An error occurred at line: 12 in the jsp file: /testdb/test-db.jsp
Generated servlet error:
TestSQLLoad cannot be resolved or is not a type
An error occurred at line: 12 in the jsp file: /testdb/test-db.jsp
Generated servlet error:
TestSQLLoad cannot be resolved or is not a type
org.apache.jasper.compiler.DefaultErrorHandler.javacError(DefaultErrorHandler.j ava:84)
org.apache.jasper.compiler.ErrorDispatcher.javacError(ErrorDispatcher.java:328)
org.apache.jasper.compiler.JDTCompiler.generateClass(JDTCompiler.java:389)
org.apache.jasper.compiler.Compiler.compile(Compiler.java:288)
org.apache.jasper.compiler.Compiler.compile(Compiler.java:267)
org.apache.jasper.compiler.Compiler.compile(Compiler.java:255)
org.apache.jasper.JspCompilationContext.compile(JspCompilationContext.java:556)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:296)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:295)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:245)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
note The full stack trace of the root cause is available in the Apache Tomcat/5.5.4 logs.
AND NOW WHEN just to get rid of such errords i try to include a statement
<%@ page import="pkg.TestSQLLoad" %> in the jsp page code (and also place the MySQLLoad.class file in a folder called pkg and place it in the same directory where the jsp page is )and make it look like
<html>
<head>
<%@ page import="pkg.TestSQLLoad" %>
<title>DB Test</title>
</head>
<body>
<%
TestSQLLoad tst = new TestSQLLoad ( );
tst.init();
%>
<h2>Results</h2>
User <%= tst.getUser() %>
Pwd <%= tst.getPassword() %>
Id <%= tst.getID() %>
</body>
</html>
now when i run it i get the following errors:
exception
org.apache.jasper.JasperException: Unable to compile class for JSP
Generated servlet error:
Only a type can be imported. pkg.TestSQLLoad resolves to a package
An error occurred at line: 12 in the jsp file: /testdb/test-db.jsp
Generated servlet error:
TestSQLLoad cannot be resolved or is not a type
An error occurred at line: 12 in the jsp file: /testdb/test-db.jsp
Generated servlet error:
TestSQLLoad cannot be resolved or is not a type
org.apache.jasper.compiler.DefaultErrorHandler.javacError(DefaultErrorHandler.j ava:84)
org.apache.jasper.compiler.ErrorDispatcher.javacError(ErrorDispatcher.java:328)
org.apache.jasper.compiler.JDTCompiler.generateClass(JDTCompiler.java:389)
org.apache.jasper.compiler.Compiler.compile(Compiler.java:288)
org.apache.jasper.compiler.Compiler.compile(Compiler.java:267)
org.apache.jasper.compiler.Compiler.compile(Compiler.java:255)
org.apache.jasper.JspCompilationContext.compile(JspCompilationContext.java:556)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:296)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:295)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:245)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
in response to the above error i have even tried placing the MySQLLoad.class directly in the testdb folder along with the jsp page without keeping it in a package named pkg and then importing directly as <@page import="MySQLLoad" %>
that too gave me the following errors
org.apache.jasper.JasperException: Unable to compile class for JSP
Generated servlet error:
The import TestSQLLoad cannot be resolved
An error occurred at line: 12 in the jsp file: /testdb/test-db.jsp
Generated servlet error:
TestSQLLoad cannot be resolved or is not a type
An error occurred at line: 12 in the jsp file: /testdb/test-db.jsp
Generated servlet error:
TestSQLLoad cannot be resolved or is not a type
org.apache.jasper.compiler.DefaultErrorHandler.javacError(DefaultErrorHandler.j ava:84)
org.apache.jasper.compiler.ErrorDispatcher.javacError(ErrorDispatcher.java:328)
org.apache.jasper.compiler.JDTCompiler.generateClass(JDTCompiler.java:389)
org.apache.jasper.compiler.Compiler.compile(Compiler.java:288)
org.apache.jasper.compiler.Compiler.compile(Compiler.java:267)
org.apache.jasper.compiler.Compiler.compile(Compiler.java:255)
org.apache.jasper.JspCompilationContext.compile(JspCompilationContext.java:556)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:296)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:295)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:245)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
and if i do not use the statement <%@ page import="MySQLLoad"%> then also i get the errors like
org.apache.jasper.JasperException: Unable to compile class for JSP
An error occurred at line: 11 in the jsp file: /testdb/test-db.jsp
Generated servlet error:
TestSQLLoad cannot be resolved or is not a type
An error occurred at line: 11 in the jsp file: /testdb/test-db.jsp
Generated servlet error:
TestSQLLoad cannot be resolved or is not a type
org.apache.jasper.compiler.DefaultErrorHandler.javacError(DefaultErrorHandler.j ava:84)
org.apache.jasper.compiler.ErrorDispatcher.javacError(ErrorDispatcher.java:328)
org.apache.jasper.compiler.JDTCompiler.generateClass(JDTCompiler.java:389)
org.apache.jasper.compiler.Compiler.compile(Compiler.java:288)
org.apache.jasper.compiler.Compiler.compile(Compiler.java:267)
org.apache.jasper.compiler.Compiler.compile(Compiler.java:255)
org.apache.jasper.JspCompilationContext.compile(JspCompilationContext.java:556)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:296)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:295)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:245)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
THE 2nd Method:
in my second method i did the same changes in the web.xml and server.xml
then i took a jsp page with the following code:
<%@ page import="javax.sql.*,java.sql.*,javax.naming.*,com.mysql.jdbc.*" %>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML>
<HEAD>
<TITLE> trial doc </TITLE>
</HEAD>
<BODY>
<h1>Trial Document</h1>
<% InitialContext context=new InitialContext( );
DataSource dataSource=(DataSource) context.lookup("java:comp/env/jdbc/testdb");
Connection conn=dataSource.getConnection();
Statement stmt=conn.createStatement();
ResultSet rset=stmt.executeQuery("select * from user");
if (rset.next()){
%>
<table width="100%" border="1">
<tr align="left">
<th>name</th> <th>password</th><th>id</th>
</tr>
<%
do {
%>
<tr><td> <%=rset.getString(1)%> </td>
<td><%=rset.getString(2) %></td>
<td><%=rset.getString(3) %></td></tr>
<%
} while (rset.next());
%>
</table>
<%
} else{
%>
No results from query
<%
rset.close();
stmt.close();
conn.close();
context.close();
%>
</BODY>
</HTML>
org.apache.jasper.JasperException: Unable to compile class for JSP
An error occurred at line: 15 in the jsp file: /testdb/Big1.jsp
Generated servlet error:
The type Connection is ambiguous
An error occurred at line: 15 in the jsp file: /testdb/Big1.jsp
Generated servlet error:
The type Statement is ambiguous
An error occurred at line: 15 in the jsp file: /testdb/Big1.jsp
Generated servlet error:
The type ResultSet is ambiguous
org.apache.jasper.compiler.DefaultErrorHandler.javacError(DefaultErrorHandler.j ava:84)
org.apache.jasper.compiler.ErrorDispatcher.javacError(ErrorDispatcher.java:328)
org.apache.jasper.compiler.JDTCompiler.generateClass(JDTCompiler.java:389)
org.apache.jasper.compiler.Compiler.compile(C

thanx for ur response
as u said that the problem is more of a jsp page not getting compiled....
me also pointed towards the similar situation providing all the surrounding situations
which i have met and gone through
i m still thinking that problem may b in the tomcat's server.xml and web.xml as well
so better if u plz guide me in that regard
regards,
kuldeep

Mysql connection through netbeans problem

Hi All - I am trying to connect to a mysql database using the following:
Connection con = DriverManager.getConnection("jdbc:mysql://localhost/database?" +
"user=user&password=pass");But am getting an error of: SQLException: No suitable driver found for jdbc:mysql://local...
I have downloaded MySQL Connector/J and have added it to the netbeans project libraries and still nothing works. Has anyone any idea what I am doing wrong? Thanks

Because you haven't loaded the Driver yet, either with Class.forName or DriverManager.registerDriver.
Also, I hope your user is really "user" and your password really "pass", because if "user" and "pass" are variables names that url won't work anyway. And, in anycase, you're better off using the getConnection(url, user, pass) form of getConnection anyway.

Cannot get a connection, pool error Timeout waiting for idle object

my connection pool setting is
maxActive="3" minIdle="2"                maxWait="10000"              removeAbandoed="true" logAbandoned="true"         removeAbandonedTimeout="30"         autoreconnection="true"
we have 7 people hitting the group of search functions ,
about 3 minutes I get
I got error like
org.apache.tomcat.dbcp.dbcp.SQLNestedException: Cannot get a connection, pool error Timeout waiting for idle object         at org.apache.tomcat.dbcp.dbcp.PoolingDataSource.getConnection(PoolingDataSource.java:104)         at org.apache.tomcat.dbcp.dbcp.BasicDataSource.getConnection(BasicDataSource.java:880)         at Deferment.showResult.checStudent(showResult.java:135)         at Deferment.showResult.doPost(showResult.java:99)         at javax.servlet.http.HttpServlet.service(HttpServlet.java:710)         at javax.servlet.http.HttpServlet.service(HttpServlet.java:803)         at org.apache.catalina.servlets.InvokerServlet.serveRequest(InvokerServlet.java:402)         at org.apache.catalina.servlets.InvokerServlet.doPost(InvokerServlet.java:170)         at javax.servlet.http.HttpServlet.service(HttpServlet.java:710)         at javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
I just wonder
1) Cannot get a connection, pool error Timeout waiting for idle object-> cause by connection pool leaking or other problem.
2) Setting the maxactive to -1 ( suggestion from Google) , if I set my connection to ulimit , waht should I put on minIdle="2"
3) How can I test my connection pool have problem or not ? is
SHOW PROCESSLIST; tolding me someinformation? I use Mysql
Thank you!

I try something like ps2 = conn.prepareStatement(target);
            ps2.setString(1, UNumber); // set input parameter
            rs = ps2.executeQuery();
            sendMail = 0;//how many rows we can find.
            while (rs.next()) {
                sendMail++;
            ps2.close();
            rs.close();
            conn.close();
if ((count1 == 0) || (count2 == 0)) {
                conn.rollback();
            } else {
                conn.commit();
                conn.setAutoCommit(true);
            ps.close();
            calstat2.close();
            conn.close();
calstat = (CallableStatement) conn.prepareCall("{call findStudent}");
            calstat.executeQuery();
            calstat.close();
            conn.close();is that enought? what else I should do to make sure I did close all the connection, after I use it ?
thank you

Tomcat Connection pooling problem

I am using Tomcat connection pooling (DBCP) to get the connection from the Database
It really works great with Oracle, MySQL, Sybase and as well as DB2.
Recently I tried to integrate apache with tomcat to improve the performance.
But now the problem is I am unable to load the JDBC Driver its giving me an error message as Cannot load JDBC driver class ?null?
@ org.apache.commons.dbcp.BasicDataSource.createDataSource ..
Interseting thing is I am able to get connection through datasource(DBCP) if I use the following URL
http://localhost:8080/application _name/Hello.jsp
But I get the error message when I try to get connection through datasource(DBCP)
as Cannot load JDBC driver class ?null? for this URL
http://localhost/application_name/Hello.jsp
Both the URL use same server.xml, httpd.conf,servlet class and jsp pages
Gurus can you please help me to understand why my application is unable to get the connection when I use this URL http://localhost/application_name/Hello.jsp
But not with other one
Please........... Some one help me
Thanks in Advance
Maria

How did you make Tomcat connection pooling(DBCP) working with Oracle?
I refereced to the "JNDI Datasource HOW-TO" in Jakarta Tomcat. I am using Tomcat 4.18. I can get DataSource object, but when to get connection from dataSource, not any response, It seems freezing.
I appreciate any reply.
Johnson Ouyang

MySQL connection pooling (tomcat) problem

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