Hey guys,
I have a question about the classloader...
When reading the following message, please keep in the back of your mind
that my application does NOT reside in the default webapps directory...
I created my own virtual host, with its context in a location like
/var/www/mywebapp. I don't think this should matter, but it might...
Also, please excuse the html tags...I tried to post this to another board,
and I am just plain tired of writing and wasting 5 hours today trying to
solve this problem.
Message:
<p>Hey all,</p>
<p>I have a problem that is driving me nuts...and I'm an experienced Tomcat
user, so this is killing me.</p>
<p>I'm using Tomcat 4.0.3 LE / jdk 1.4.0-b92</p>
<p>Tomcat cannot find classes I place in a package, yet if I remove the
package statement from the file, and just move the file to
mywebapp/WEB-INF/classes, then tomcat can find it.</p>
<p>when I place the .java file in the proper package directory with the
cooresponding package statement in the file, and I try to run my webapp,
tomcat throws an InstantiationException.</p>
<p>I then went to the actual translated jsp page turned into servlet (the
mypage$jsp.java file Tomcat generates) and find that the error is not really
an InstantiationException...its a ClassNotFoundException. i.e., the
mypage$jsp.java file just catches the ClassNotFoundException and then
immediately throws the InstantiationException.</p>
<p>So now I know that Tomcat can't find the file, not just that it can't
instantiate it...but I'm baffled, because the file is in the correct
place.</p>
<p>This is the setup:</p>
<p>my compiled class (DatabaseWrapper class) is located in:<br>
mywebapp/WEB-INF/classes/com/leshazlewood/cs4400/util/DatabaseWrapper.class<
/p>
<p>the package statement IN (and the 1st line) of this file is:<br>
package com.leshazlewood.cs4400.util;</p>
<p>When in this structure, Tomcat throws the ClassNotFoundException.</p>
<p>When I take it out of the package, and move it to WEB-INF/classes, Tomcat
finds and instantiates the class just fine.</p>
<p>For your convenience, I've included the java class file WITH the package
statement included. This is how it is SUPPOSED to be, and how I would like
it. This is then followed by Tomcat's error page output.</p>
<p>MANY Thanks in advance!!!</p>
<p>Les</p>
<hl>
<center>Java Code Follows:</center>
<p>
<pre>
package com.leshazlewood.cs4400.util;
import java.sql.*;
import java.util.*;
import java.io.*;
import com.javaexchange.dbConnectionBroker.*;
/** A singleton class for wrapping the database for access by other
application tiers.
* Also implements connection pooling.
*
* @author Les A. Hazlewood
* @version 0.1, 11/03/01
*/
public class DatabaseWrapper
{
protected static DbConnectionBroker connBroker = null;
protected static boolean conPoolReady = false;
public DatabaseWrapper(){}
public static void initConPool()
{
try
{
connBroker = new DbConnectionBroker(Constants.DB_DRIVER,
Constants.DB_JDBC_STRING,
Constants.DB_USERNAME,
Constants.DB_PASSWORD,
Constants.DB_POOL_MIN_CONS,
Constants.DB_POOL_MAX_CONS,
Constants.DB_POOL_LOG_FILE,
Constants.DB_POOL_MAX_CON_TIME);
conPoolReady = true;
}
catch (IOException ioe){}
}
public static synchronized Connection getConnection()
{
Connection conn;
if (!conPoolReady)
initConPool();
conn = connBroker.getConnection();
return conn;
} //ends getConnection()
public static synchronized void closeConnection(Connection conn)
{
try
{
//don't actually close it...put it back in the pool:
if (conn != null)
{
//some beans may have turned off autocommit...so
//turn it back on here so other beans that use it
//will have the default behavior:
conn.setAutoCommit(true);
connBroker.freeConnection(conn);
}
}
catch (Exception e)
{
e.printStackTrace();
}
}
}// ends class DatabaseWrapper
</pre>
</p>
<hl>
<center>Tomcat's Error Page Output Follows:</center>
<p>
<pre>
javax.servlet.ServletException: DatabaseWrapper
at
org.apache.jasper.runtime.PageContextImpl.handlePageException(PageContextImp
l.java:463)
at org.apache.jsp.custMembApp$jsp._jspService(custMembApp$jsp.java:374)
at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:107)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:853)
at
org.apache.jasper.servlet.JspServlet$JspServletWrapper.service(JspServlet.ja
va:202)
at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:382)
at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:474)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:853)
at
org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(Application
FilterChain.java:247)
at
org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterCh
ain.java:193)
at
org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.ja
va:243)
at
org.apache.catalina.core.StandardPipeline.invokeNext(StandardPipeline.java:5
66)
at
org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:472)
at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:943)
at
org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.ja
va:190)
at
org.apache.catalina.core.StandardPipeline.invokeNext(StandardPipeline.java:5
66)
at
org.apache.catalina.valves.CertificatesValve.invoke(CertificatesValve.java:2
46)
at
org.apache.catalina.core.StandardPipeline.invokeNext(StandardPipeline.java:5
64)
at
org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:472)
at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:943)
at
org.apache.catalina.core.StandardContext.invoke(StandardContext.java:2343)
at
org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:180
)
at
org.apache.catalina.core.StandardPipeline.invokeNext(StandardPipeline.java:5
66)
at
org.apache.catalina.valves.ErrorDispatcherValve.invoke(ErrorDispatcherValve.
java:170)
at
org.apache.catalina.core.StandardPipeline.invokeNext(StandardPipeline.java:5
64)
at
org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:170
)
at
org.apache.catalina.core.StandardPipeline.invokeNext(StandardPipeline.java:5
64)
at
org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:472)
at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:943)
at
org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java
:174)
at
org.apache.catalina.core.StandardPipeline.invokeNext(StandardPipeline.java:5
66)
at
org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:472)
at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:943)
at
org.apache.catalina.connector.warp.WarpRequestHandler.handle(WarpRequestHand
ler.java:217)
at
org.apache.catalina.connector.warp.WarpConnection.run(WarpConnection.java:19
4)
at java.lang.Thread.run(Thread.java:536)
root cause
java.lang.InstantiationException: DatabaseWrapper
at org.apache.jsp.custMembApp$jsp._jspService(custMembApp$jsp.java:86)
at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:107)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:853)
at
org.apache.jasper.servlet.JspServlet$JspServletWrapper.service(JspServlet.ja
va:202)
at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:382)
at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:474)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:853)
at
org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(Application
FilterChain.java:247)
at
org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterCh
ain.java:193)
at
org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.ja
va:243)
at
org.apache.catalina.core.StandardPipeline.invokeNext(StandardPipeline.java:5
66)
at
org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:472)
at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:943)
at
org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.ja
va:190)
at
org.apache.catalina.core.StandardPipeline.invokeNext(StandardPipeline.java:5
66)
at
org.apache.catalina.valves.CertificatesValve.invoke(CertificatesValve.java:2
46)
at
org.apache.catalina.core.StandardPipeline.invokeNext(StandardPipeline.java:5
64)
at
org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:472)
at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:943)
at
org.apache.catalina.core.StandardContext.invoke(StandardContext.java:2343)
at
org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:180
)
at
org.apache.catalina.core.StandardPipeline.invokeNext(StandardPipeline.java:5
66)
at
org.apache.catalina.valves.ErrorDispatcherValve.invoke(ErrorDispatcherValve.
java:170)
at
org.apache.catalina.core.StandardPipeline.invokeNext(StandardPipeline.java:5
64)
at
org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:170
)
at
org.apache.catalina.core.StandardPipeline.invokeNext(StandardPipeline.java:5
64)
at
org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:472)
at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:943)
at
org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java
:174)
at
org.apache.catalina.core.StandardPipeline.invokeNext(StandardPipeline.java:5
66)
at
org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:472)
at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:943)
at
org.apache.catalina.connector.warp.WarpRequestHandler.handle(WarpRequestHand
ler.java:217)
at
org.apache.catalina.connector.warp.WarpConnection.run(WarpConnection.java:19
4)
at java.lang.Thread.run(Thread.java:536)
</pre>
</p>
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