Help Preventing VM Tomcat Crash
I'm working on a servlet that shrinks JPEG photos on the fly to create
thumbnails. When the user selects the thumbnail page, a JSP generates HTML
that results in many calls to the thumbnail servlet. If the user is
patient and waits for all of the thumbnails to load, everything works great
-- they can click on a thumbnail to see the full-size version of that
JPEG. However, if the use clicks on a photo while they are still loading,
I get the exception dump and crash shown at the bottom. Any help greatly
appreciated! Regards, Kennedy
Here is my thumbnail servlet:
/*
* Note: JPEG manipulation code comes from Sun:
* http://developer.java.sun.com/developer/TechTips/1999/tt1021.html#tip1
*/
package gallery.servlet;
import java.io.*;
import java.text.*;
import java.util.*;
import javax.servlet.*;
import javax.servlet.http.*;
import java.awt.Image;
import java.awt.Graphics2D;
import java.awt.geom.AffineTransform;
import java.awt.image.BufferedImage;
import javax.swing.ImageIcon;
import com.sun.image.codec.jpeg.JPEGCodec;
import com.sun.image.codec.jpeg.JPEGImageEncoder;
/**
* Return a thumbnail of the image specified in the name parameter
*/
public class Thumbnail extends HttpServlet {
public void doGet(HttpServletRequest request,
HttpServletResponse response)
throws IOException, ServletException
{
response.setContentType(image/jpeg);
File f = new File(request.getParameter(name));
if (!f.exists())
return;
OutputStream os = response.getOutputStream();
createThumbnail(request.getParameter(name), os, 150);
}
/**
* Reads an image in a file and creates a thumbnail to the output stream
*
* @param orig The name of image file.
* @param thumb The name of thumbnail file.
* Will be created if necessary.
* @param maxDim The width and height of the thumbnail must
* be maxDim pixels or less.
*/
public static void createThumbnail(String orig, OutputStream os, int
maxDim) {
try {
// Get the image from a file.
Image inImage = new ImageIcon(orig).getImage();
// Determine the scale.
double scale = (double)maxDim/(double)inImage.getHeight(null);
if (inImage.getWidth(null) inImage.getHeight(null)) {
scale = (double)maxDim/(double)inImage.getWidth(null);
}
// Determine size of new image.
// One of them should equal maxDim.
int scaledW = (int)(scale*inImage.getWidth(null));
int scaledH = (int)(scale*inImage.getHeight(null));
// Create an image buffer in which to paint on.
BufferedImage outImage =
new BufferedImage(scaledW, scaledH, BufferedImage.TYPE_INT_RGB);
// Set the scale.
AffineTransform tx = new AffineTransform();
// If the image is smaller than
//the desired image size,
// don't bother scaling.
if (scale 1.0d) {
tx.scale(scale, scale);
}
// Paint image.
Graphics2D g2d = outImage.createGraphics();
g2d.drawImage(inImage, tx, null);
g2d.dispose();
// JPEG-encode the image and write to file.
//OutputStream os = new FileOutputStream(thumb);
JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(os);
encoder.encode(outImage);
//os.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
And here is the exception/crash:
java.io.IOException: reading encoded JPEG Stream
at sun.awt.image.codec.JPEGImageEncoderImpl.writeJPEGStream(Native
Method)
at
sun.awt.image.codec.JPEGImageEncoderImpl.encode(JPEGImageEncoderImpl.java:475)
at
sun.awt.image.codec.JPEGImageEncoderImpl.encode(JPEGImageEncoderImpl.java:231)
at gallery.servlet.Thumbnail.createThumbnail(Thumbnail.java:85)
at gallery.servlet.Thumbnail.doGet(Thumbnail.java:35)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:740)
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.doFilter(ApplicationFilterChain.java:193)
at
org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:243)
at
org.apache.catalina.core.StandardPipeline.invokeNext(StandardPipeline.java:566)
at
org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:472)
at
org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:943)
at
RE: Help Preventing VM Tomcat Crash
Looks like you are using the JDBC-ODBC bridge (maybe to an MS Access or MS
SQL Server database?), which is not thread-safe and is not intended for use
in production environments. My guess is that one thread (the current thread
servicing the Thumbnail servlet) has a db connection open, and the next
request (the user clicking the thumbnail) opens another db connection. This
guess is based on these lines in your exception:
An unexpected exception has been detected in native code outside the VM.
Unexpected Signal : unknown exception code occurred at PC=0x77fb16cc
Function name=RtlTraceDatabaseEnumerate
Library=C:\WINNT\System32\ntdll.dll
If this is the case, try finding a pure Java (type 4) JDBC driver for your
database.
Shawn
-Original Message-
From: Kennedy Clark [mailto:[EMAIL PROTECTED]]
Sent: Saturday, February 23, 2002 5:36 AM
To: [EMAIL PROTECTED]
Subject: Help Preventing VM Tomcat Crash
I'm working on a servlet that shrinks JPEG photos on the fly to create
thumbnails. When the user selects the thumbnail page, a JSP generates HTML
that results in many calls to the thumbnail servlet. If the user is
patient and waits for all of the thumbnails to load, everything works great
-- they can click on a thumbnail to see the full-size version of that
JPEG. However, if the use clicks on a photo while they are still loading,
I get the exception dump and crash shown at the bottom. Any help greatly
appreciated! Regards, Kennedy
Here is my thumbnail servlet:
/*
* Note: JPEG manipulation code comes from Sun:
* http://developer.java.sun.com/developer/TechTips/1999/tt1021.html#tip1
*/
package gallery.servlet;
import java.io.*;
import java.text.*;
import java.util.*;
import javax.servlet.*;
import javax.servlet.http.*;
import java.awt.Image;
import java.awt.Graphics2D;
import java.awt.geom.AffineTransform;
import java.awt.image.BufferedImage;
import javax.swing.ImageIcon;
import com.sun.image.codec.jpeg.JPEGCodec;
import com.sun.image.codec.jpeg.JPEGImageEncoder;
/**
* Return a thumbnail of the image specified in the name parameter
*/
public class Thumbnail extends HttpServlet {
public void doGet(HttpServletRequest request,
HttpServletResponse response)
throws IOException, ServletException
{
response.setContentType(image/jpeg);
File f = new File(request.getParameter(name));
if (!f.exists())
return;
OutputStream os = response.getOutputStream();
createThumbnail(request.getParameter(name), os, 150);
}
/**
* Reads an image in a file and creates a thumbnail to the output
stream
*
* @param orig The name of image file.
* @param thumb The name of thumbnail file.
* Will be created if necessary.
* @param maxDim The width and height of the thumbnail must
* be maxDim pixels or less.
*/
public static void createThumbnail(String orig, OutputStream os, int
maxDim) {
try {
// Get the image from a file.
Image inImage = new ImageIcon(orig).getImage();
// Determine the scale.
double scale = (double)maxDim/(double)inImage.getHeight(null);
if (inImage.getWidth(null) inImage.getHeight(null)) {
scale = (double)maxDim/(double)inImage.getWidth(null);
}
// Determine size of new image.
// One of them should equal maxDim.
int scaledW = (int)(scale*inImage.getWidth(null));
int scaledH = (int)(scale*inImage.getHeight(null));
// Create an image buffer in which to paint on.
BufferedImage outImage =
new BufferedImage(scaledW, scaledH,
BufferedImage.TYPE_INT_RGB);
// Set the scale.
AffineTransform tx = new AffineTransform();
// If the image is smaller than
//the desired image size,
// don't bother scaling.
if (scale 1.0d) {
tx.scale(scale, scale);
}
// Paint image.
Graphics2D g2d = outImage.createGraphics();
g2d.drawImage(inImage, tx, null);
g2d.dispose();
// JPEG-encode the image and write to file.
//OutputStream os = new FileOutputStream(thumb);
JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(os);
encoder.encode(outImage);
//os.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
And here is the exception/crash:
java.io.IOException: reading encoded JPEG Stream
at sun.awt.image.codec.JPEGImageEncoderImpl.writeJPEGStream(Native
Method)
at
sun.awt.image.codec.JPEGImageEncoderImpl.encode(JPEGImageEncoderImpl.java:47
5)
at
sun.awt.image.codec.JPEGImageEncoderImpl.encode(JPEGImageEncoderImpl.java:23
1)
at
Re: [Mac OS X] /examples not working
Ken, Did you make sure to use gnutar and not tar? I believe the Jakarta tar files use gnu extensions, and gnutar must be used. At least that's what I read and it got me out of a jam with a mangled pathname within Tomcat when unpacked with tar - or StuffIt, for that matter. - Ken On Friday, February 22, 2002, at 05:12 PM, Ken Martin wrote: I have gone through the list archives and can't find a solution (though this could certainly be my fault)... I have installed Tomcat 4.0.1 but I can't get the /examples to work. I did try decompressing the .tar using Stuffit, tar in Terminal, and I tried the .zip. I tried to follow the instructions at the Apple site (and I think I succeeded in following the instructions), but no /examples. I also tried to set it up for Apache and get the same error as I get at :8080. Thanks for any help/advice, Ken Martin -- To unsubscribe: mailto:[EMAIL PROTECTED] For additional commands: mailto:[EMAIL PROTECTED] Troubles with the list: mailto:[EMAIL PROTECTED] -- To unsubscribe: mailto:[EMAIL PROTECTED] For additional commands: mailto:[EMAIL PROTECTED] Troubles with the list: mailto:[EMAIL PROTECTED]
New bie problem about Tomcat
Hi, I have a problem about a servlet that I want to start on load of Tomcat. I included into the web.xml for the application under the on-load. The init method of the servlet is called two times, but not the service method of the servlet. I am not sure why the init method should get called 2 times? We are using Tomcat 4.0 on Apache. What do we do to execute a servlet on web-server startup? Krishna.
Re: Tomcat failure to start
Can someone help please?
On February 22, 2002 03:10 pm, you wrote:
Hi,
Tomcat doesn't want to start on my RedHat 7.1 system. I get this error in
my log:
usage: java org.apache.catalina.startup.Catalina [ -config {pathname} ] [
-debug ] [ -nonaming ] { start | stop }
and catalina.sh is loading
org.apache.catalina.startup.Bootstrap
Can someone help please?
--
To unsubscribe: mailto:[EMAIL PROTECTED]
For additional commands: mailto:[EMAIL PROTECTED]
Troubles with the list: mailto:[EMAIL PROTECTED]
--
To unsubscribe: mailto:[EMAIL PROTECTED]
For additional commands: mailto:[EMAIL PROTECTED]
Troubles with the list: mailto:[EMAIL PROTECTED]
Apache Tomcat/4.0.2 - HTTP Status 404 - /examples/jsp/
Yes, I am a newbie, but... Installed Tomcat 4.0.2 (precompiled version) (on Mac OS X (That's unix) ) in a directory I called Tomcat. Tomcat starts just fine with this script: #!/bin/sh export CATALINA_HOME=/Tomcat/jakarta-tomcat-4.0.2 export JAVA_HOME=/System/Library/Frameworks/JavaVM.framework/Home $CATALINA_HOME/bin/startup.sh I get the default html-pages in ROOT no problem. I can also run JSP-pages from ROOT. But nothing in examples works! (I didn't change anything during installation, and there are lots of files and folder present in examples..) Shouldn't I at least be able to expect at least the enclosed examples to run corectly out of the box?.. Terje -- To unsubscribe: mailto:[EMAIL PROTECTED] For additional commands: mailto:[EMAIL PROTECTED] Troubles with the list: mailto:[EMAIL PROTECTED]
Re: [Mac OS X] /examples not working
I used StuffIt (Deluxe). Are you saying that should be OK, or not? Terje -- To unsubscribe: mailto:[EMAIL PROTECTED] For additional commands: mailto:[EMAIL PROTECTED] Troubles with the list: mailto:[EMAIL PROTECTED]
Tomcat 4 and Apache
Hi everyone, I'm sorry that I'm probably the 100th person to ask this, but I have searched google groups and the archives of this mailing list, both of which failed to help me setting up Tomcat 4.01 with Apache 1.3.23 on Windows. I have tried to load both mod_jk.dll and mod_webapp.so in Apache. mod_jk gives me the following error: Syntax error on line 195 of c:/programme/wamp/apache/conf/httpd.conf: Can't locate API module structure `mod_jk' in file c:/programme/wamp/apache/modules/mod_jk.dll: (127) Die angegebene Prozedur wurde nicht gefunden: The last bit translates to The specified procedure was not found. The relevant lines in my httpd.conf are LoadModule mod_jk modules/mod_jk.dll AddModule mod_jk.c I had more luck with mod_webapp, which loads properly using these lines: LoadModule webapp_module modules/mod_webapp.so AddModule mod_webapp.c WebAppConnection conn warp localhost:8008 But when I add either (or both) of these lines WebAppInfo /webapp-info WebAppDeploy examples conn /examples apache -t gives me the following error: C:\Programme\Wamp\Apacheapache -t Syntax error on line 256 of c:/programme/wamp/apache/conf/httpd.conf: Invalid virtual host name where in line 256 is either one (or the first of) WebAppInfo /webapp-info WebAppDeploy examples conn /examples I have found out that other users had this problem when their ServerName directive was commented out in their httpd.conf, and I have tried that already, without luck. Does anybody have an idea how to solve this problem? Thank you very much Kristian -- To unsubscribe: mailto:[EMAIL PROTECTED] For additional commands: mailto:[EMAIL PROTECTED] Troubles with the list: mailto:[EMAIL PROTECTED]
Re: [Mac OS X] /examples not working
Excelent tip StuffIt Deluxe was no good! I now unpacked it with gnutar, an reinstalled it. And it works!! Thanks alot! (Spent weeks trying to figure out the problem) Terje -- To unsubscribe: mailto:[EMAIL PROTECTED] For additional commands: mailto:[EMAIL PROTECTED] Troubles with the list: mailto:[EMAIL PROTECTED]
Re: [Mac OS X] /examples not working
On Saturday, February 23, 2002, at 10:31 AM, Ken Pelletier wrote: Did you make sure to use gnutar and not tar? Ken, you're my hero! Works perfectly and installed instantly. A very happy weekend development! Man, this is great... I've mucked around with this for quite a while over a number of weeks. Ugh! You know, the Apple instructions use 'tar' and not 'gnutar'... boy the time adding three letters could have saved me! Thanks again! Ken Martin -- To unsubscribe: mailto:[EMAIL PROTECTED] For additional commands: mailto:[EMAIL PROTECTED] Troubles with the list: mailto:[EMAIL PROTECTED]
RE: Help Preventing VM Tomcat Crash
Hi Shawn,
Many thanks for the note the suggestion! I am using MySQL as my Db and
MM.MySQL is my driver (mm.mysql-2.0.11-bin.jar). Given that this is a Type
4 driver, I don't think I should be getting a native code crash involving
database access, right?
I could be missing something, but it seems that the
sun.awt.image.codec.JPEGImageEncoderImpl.writeJPEGStream() method (which is
native code) is trying to write to my output stream and running into
trouble. I assume this is because the user has clicked on an image serving
as a link to another web page and now Tomcat is off trying to handle the
new page. My best guess is that in the process of doing so, the output
streams used by writeJPEGStream() are being torn down, but the native code
doesn't know this and it's causing the VM to puke. Does anyone think my
logic makes sense? Better yet, does anyone know a way to prevent it? :-)
Regards, Kennedy
At 09:02 AM 2/23/2002 -0600, Shawn Church wrote:
Looks like you are using the JDBC-ODBC bridge (maybe to an MS Access or MS
SQL Server database?), which is not thread-safe and is not intended for use
in production environments. My guess is that one thread (the current thread
servicing the Thumbnail servlet) has a db connection open, and the next
request (the user clicking the thumbnail) opens another db connection. This
guess is based on these lines in your exception:
An unexpected exception has been detected in native code outside the VM.
Unexpected Signal : unknown exception code occurred at PC=0x77fb16cc
Function name=RtlTraceDatabaseEnumerate
Library=C:\WINNT\System32\ntdll.dll
If this is the case, try finding a pure Java (type 4) JDBC driver for your
database.
Shawn
-Original Message-
From: Kennedy Clark [mailto:[EMAIL PROTECTED]]
Sent: Saturday, February 23, 2002 5:36 AM
To: [EMAIL PROTECTED]
Subject: Help Preventing VM Tomcat Crash
I'm working on a servlet that shrinks JPEG photos on the fly to create
thumbnails. When the user selects the thumbnail page, a JSP generates HTML
that results in many calls to the thumbnail servlet. If the user is
patient and waits for all of the thumbnails to load, everything works great
-- they can click on a thumbnail to see the full-size version of that
JPEG. However, if the use clicks on a photo while they are still loading,
I get the exception dump and crash shown at the bottom. Any help greatly
appreciated! Regards, Kennedy
Here is my thumbnail servlet:
/*
* Note: JPEG manipulation code comes from Sun:
* http://developer.java.sun.com/developer/TechTips/1999/tt1021.html#tip1
*/
package gallery.servlet;
import java.io.*;
import java.text.*;
import java.util.*;
import javax.servlet.*;
import javax.servlet.http.*;
import java.awt.Image;
import java.awt.Graphics2D;
import java.awt.geom.AffineTransform;
import java.awt.image.BufferedImage;
import javax.swing.ImageIcon;
import com.sun.image.codec.jpeg.JPEGCodec;
import com.sun.image.codec.jpeg.JPEGImageEncoder;
/**
* Return a thumbnail of the image specified in the name parameter
*/
public class Thumbnail extends HttpServlet {
public void doGet(HttpServletRequest request,
HttpServletResponse response)
throws IOException, ServletException
{
response.setContentType(image/jpeg);
File f = new File(request.getParameter(name));
if (!f.exists())
return;
OutputStream os = response.getOutputStream();
createThumbnail(request.getParameter(name), os, 150);
}
/**
* Reads an image in a file and creates a thumbnail to the output
stream
*
* @param orig The name of image file.
* @param thumb The name of thumbnail file.
* Will be created if necessary.
* @param maxDim The width and height of the thumbnail must
* be maxDim pixels or less.
*/
public static void createThumbnail(String orig, OutputStream os, int
maxDim) {
try {
// Get the image from a file.
Image inImage = new ImageIcon(orig).getImage();
// Determine the scale.
double scale = (double)maxDim/(double)inImage.getHeight(null);
if (inImage.getWidth(null) inImage.getHeight(null)) {
scale = (double)maxDim/(double)inImage.getWidth(null);
}
// Determine size of new image.
// One of them should equal maxDim.
int scaledW = (int)(scale*inImage.getWidth(null));
int scaledH = (int)(scale*inImage.getHeight(null));
// Create an image buffer in which to paint on.
BufferedImage outImage =
new BufferedImage(scaledW, scaledH,
BufferedImage.TYPE_INT_RGB);
// Set the scale.
AffineTransform tx = new AffineTransform();
// If the image is smaller than
//the
RE: Help Preventing VM Tomcat Crash
So much for that theory.
However, your guess is pretty close. I found something which you might find
interesting. This is a known bug, which you can check out here:
http://developer.java.sun.com/developer/bugParade/bugs/4502892.html
The problem occurs when the socket is prematurely closed. The workaround is
to buffer the output via ByteArrayOutputStream, isolating the native method
from stream disconnections.
The evaluation of the bug I will include here for convenience:
***
The JPEG library is not MT-safe. In particular, there is a definition of
a global variable struct error_mgr ek_err which is used by all threads
for error handling -- including a setjmp buffer. Consequently, when an
error does occur while more than one thread is executing in the native
library, it is common for that thread to longjmp to another thread's state.
It then uses the wrong JNIEnv pointer and trashes the VM.
x@x 2001-10-09
This bug has indeed been fixed in merlin-rc1, but its associated regression
test
(JPEGMultithread.java) is confusing and potentially misleading. This is
addressed by another bug (4546112 - Reg-test JPEGMultithread.java Failing).
The regression test currently throws exceptions endlessly if bug 4502892 is
not
present, and hangs or crashes the VM if bug 4502892 is present. This is bad
behavior for a regression test, so it will be updated in accordance with
4546112.
x@x 2001-12-19
***
Hope this helps more,
Shawn
-Original Message-
From: Kennedy Clark [mailto:[EMAIL PROTECTED]]
Sent: Saturday, February 23, 2002 2:32 PM
To: Tomcat Users List
Subject: RE: Help Preventing VM Tomcat Crash
Hi Shawn,
Many thanks for the note the suggestion! I am using MySQL as my Db and
MM.MySQL is my driver (mm.mysql-2.0.11-bin.jar). Given that this is a Type
4 driver, I don't think I should be getting a native code crash involving
database access, right?
I could be missing something, but it seems that the
sun.awt.image.codec.JPEGImageEncoderImpl.writeJPEGStream() method (which is
native code) is trying to write to my output stream and running into
trouble. I assume this is because the user has clicked on an image serving
as a link to another web page and now Tomcat is off trying to handle the
new page. My best guess is that in the process of doing so, the output
streams used by writeJPEGStream() are being torn down, but the native code
doesn't know this and it's causing the VM to puke. Does anyone think my
logic makes sense? Better yet, does anyone know a way to prevent it? :-)
Regards, Kennedy
At 09:02 AM 2/23/2002 -0600, Shawn Church wrote:
Looks like you are using the JDBC-ODBC bridge (maybe to an MS Access or MS
SQL Server database?), which is not thread-safe and is not intended for use
in production environments. My guess is that one thread (the current
thread
servicing the Thumbnail servlet) has a db connection open, and the next
request (the user clicking the thumbnail) opens another db connection.
This
guess is based on these lines in your exception:
An unexpected exception has been detected in native code outside the VM.
Unexpected Signal : unknown exception code occurred at PC=0x77fb16cc
Function name=RtlTraceDatabaseEnumerate
Library=C:\WINNT\System32\ntdll.dll
If this is the case, try finding a pure Java (type 4) JDBC driver for your
database.
Shawn
-Original Message-
From: Kennedy Clark [mailto:[EMAIL PROTECTED]]
Sent: Saturday, February 23, 2002 5:36 AM
To: [EMAIL PROTECTED]
Subject: Help Preventing VM Tomcat Crash
I'm working on a servlet that shrinks JPEG photos on the fly to create
thumbnails. When the user selects the thumbnail page, a JSP generates HTML
that results in many calls to the thumbnail servlet. If the user is
patient and waits for all of the thumbnails to load, everything works great
-- they can click on a thumbnail to see the full-size version of that
JPEG. However, if the use clicks on a photo while they are still loading,
I get the exception dump and crash shown at the bottom. Any help greatly
appreciated! Regards, Kennedy
Here is my thumbnail servlet:
/*
* Note: JPEG manipulation code comes from Sun:
* http://developer.java.sun.com/developer/TechTips/1999/tt1021.html#tip1
*/
package gallery.servlet;
import java.io.*;
import java.text.*;
import java.util.*;
import javax.servlet.*;
import javax.servlet.http.*;
import java.awt.Image;
import java.awt.Graphics2D;
import java.awt.geom.AffineTransform;
import java.awt.image.BufferedImage;
import javax.swing.ImageIcon;
import com.sun.image.codec.jpeg.JPEGCodec;
import com.sun.image.codec.jpeg.JPEGImageEncoder;
/**
* Return a thumbnail of the image specified in the name parameter
*/
public class Thumbnail extends HttpServlet {
public void doGet(HttpServletRequest request,
HttpServletResponse response)
throws IOException, ServletException
{
response.setContentType(image/jpeg);
File f = new
RE: Help Preventing VM Tomcat Crash
One more thing. There is a fix in jdk1.4.0 which addresses this problem, where the native code exception is handled correctly. With this version, the IOExceptions may be caught and treated as normal behavior. Here's the fix: http://developer.java.sun.com/developer/bugParade/bugs/4546112.html Shawn -Original Message- From: Shawn Church [mailto:[EMAIL PROTECTED]] Sent: Saturday, February 23, 2002 3:32 PM To: Tomcat Users List Subject: RE: Help Preventing VM Tomcat Crash So much for that theory. However, your guess is pretty close. I found something which you might find interesting. This is a known bug, which you can check out here: http://developer.java.sun.com/developer/bugParade/bugs/4502892.html The problem occurs when the socket is prematurely closed. The workaround is to buffer the output via ByteArrayOutputStream, isolating the native method from stream disconnections. The evaluation of the bug I will include here for convenience: *** The JPEG library is not MT-safe. In particular, there is a definition of a global variable struct error_mgr ek_err which is used by all threads for error handling -- including a setjmp buffer. Consequently, when an error does occur while more than one thread is executing in the native library, it is common for that thread to longjmp to another thread's state. It then uses the wrong JNIEnv pointer and trashes the VM. x@x 2001-10-09 This bug has indeed been fixed in merlin-rc1, but its associated regression test (JPEGMultithread.java) is confusing and potentially misleading. This is addressed by another bug (4546112 - Reg-test JPEGMultithread.java Failing). The regression test currently throws exceptions endlessly if bug 4502892 is not present, and hangs or crashes the VM if bug 4502892 is present. This is bad behavior for a regression test, so it will be updated in accordance with 4546112. x@x 2001-12-19 *** Hope this helps more, Shawn -Original Message- From: Kennedy Clark [mailto:[EMAIL PROTECTED]] Sent: Saturday, February 23, 2002 2:32 PM To: Tomcat Users List Subject: RE: Help Preventing VM Tomcat Crash Hi Shawn, Many thanks for the note the suggestion! I am using MySQL as my Db and MM.MySQL is my driver (mm.mysql-2.0.11-bin.jar). Given that this is a Type 4 driver, I don't think I should be getting a native code crash involving database access, right? I could be missing something, but it seems that the sun.awt.image.codec.JPEGImageEncoderImpl.writeJPEGStream() method (which is native code) is trying to write to my output stream and running into trouble. I assume this is because the user has clicked on an image serving as a link to another web page and now Tomcat is off trying to handle the new page. My best guess is that in the process of doing so, the output streams used by writeJPEGStream() are being torn down, but the native code doesn't know this and it's causing the VM to puke. Does anyone think my logic makes sense? Better yet, does anyone know a way to prevent it? :-) Regards, Kennedy At 09:02 AM 2/23/2002 -0600, Shawn Church wrote: Looks like you are using the JDBC-ODBC bridge (maybe to an MS Access or MS SQL Server database?), which is not thread-safe and is not intended for use in production environments. My guess is that one thread (the current thread servicing the Thumbnail servlet) has a db connection open, and the next request (the user clicking the thumbnail) opens another db connection. This guess is based on these lines in your exception: An unexpected exception has been detected in native code outside the VM. Unexpected Signal : unknown exception code occurred at PC=0x77fb16cc Function name=RtlTraceDatabaseEnumerate Library=C:\WINNT\System32\ntdll.dll If this is the case, try finding a pure Java (type 4) JDBC driver for your database. Shawn -Original Message- From: Kennedy Clark [mailto:[EMAIL PROTECTED]] Sent: Saturday, February 23, 2002 5:36 AM To: [EMAIL PROTECTED] Subject: Help Preventing VM Tomcat Crash I'm working on a servlet that shrinks JPEG photos on the fly to create thumbnails. When the user selects the thumbnail page, a JSP generates HTML that results in many calls to the thumbnail servlet. If the user is patient and waits for all of the thumbnails to load, everything works great -- they can click on a thumbnail to see the full-size version of that JPEG. However, if the use clicks on a photo while they are still loading, I get the exception dump and crash shown at the bottom. Any help greatly appreciated! Regards, Kennedy Here is my thumbnail servlet: /* * Note: JPEG manipulation code comes from Sun: * http://developer.java.sun.com/developer/TechTips/1999/tt1021.html#tip1 */ package gallery.servlet; import java.io.*; import java.text.*; import java.util.*; import javax.servlet.*; import javax.servlet.http.*; import java.awt.Image; import java.awt.Graphics2D; import java.awt.geom.AffineTransform; import java.awt.image.BufferedImage;
RE: TC4 and cgi
Jared, Ironically, I also was trying to get the CGIServlet to work on Friday with great difficulty. I believe I got it to work (although I am not a Perl person). I am using tomcat on Windows 2000 and I just wanted to invoke an test executable batch file (test.bat) just to see if I could get the ting to work. I assume you can replace what I did with your perl scripts and be on your way. One flaw I noticed in the documentation for the CGIServlet is that the example does not work in TC 4.0.2 unless you specify a cgiPathPrefix of WEB-INF/cgi. The default is actually a null value and so no path is added to the base of the web application. For example, if the web application is at path /foo and you do not specify a cgiPathPrefix, then when you enter http://localhost/foo/cgi-bin/test.bat it looks at the /foo directory. At least the source code and testing proved otherwise. I hope some contributor will read this and verify and correct this. I'm new to this list so I don't know the ropes too well. I am using TC as a web server and have not attempted to integrate it with Apache HTTP Server. Of course, the Apache Server can handle the CGI requests for you too. Anyway, here's some snippets from the web.xml file for a web application in TC 4.0.2. My web application has a path of /foo for the web.xml file is at /foo/WEB-INF/web.xml and I create the directory named cgi in the /foo/WEB-INF directory. I renamed just the servlets-cgi.renametojar since I only needed the CGI capability. Now I just need to hook into the CGI I want to use (Crystal Reports CGI interface). servlet servlet-namecgi/servlet-name servlet-classorg.apache.catalina.servlets.CGIServlet/servlet-class init-param param-namecgiPathPrefix/param-name param-valueWEB-INF/cgi/param-value /init-param init-param param-namedebug/param-name param-value99/param-value /init-param /servlet servlet-mapping servlet-namecgi/servlet-name url-pattern/cgi-bin/*/url-pattern /servlet-mapping Hope this helps, bill -Original Message- From: Jared Nedzel [mailto:[EMAIL PROTECTED]] Sent: Friday, February 22, 2002 12:17 PM To: Tomcat Users List Subject: Re: TC4 and cgi Paul: That doesn't appear to me to be the case, given that TC 4 has a bunch of stuff in web.xml concerning CGIs. For example there are entries in web.xml like: !-- IMPORTANT: To use the CGI servlet, you also need to rename the !--$CATALINA_HOME/server/lib/servlets-ssi.renametojar file !--to $CATALINA_HOME/server/lib/servlets-ssi.jar and: !-- Common Gateway Includes (CGI) processing servlet, which supports !-- execution of external applications that conform to the CGI spec !-- requirements. Typically, this servlet is mapped to the URL pattern !-- /cgi-bin/*, which means that any CGI applications that are !-- executed must be present within the web application. This servlet !-- supports the following initialization parameters (default values !-- are in square brackets): !-- !-- cgiPathPrefix The CGI search path will start at !-- webAppRootDir + File.separator + this prefix. !-- [WEB-INF/cgi] !-- !-- clientInputTimeout The time (in milliseconds) to wait for input !-- from the browser before assuming that there !-- is none. [100] !-- !-- debug Debugging detail level for messages logged !-- by this servlet. [0] !-- IMPORTANT: To use the CGI servlet, you also need to rename the !--$CATALINA_HOME/server/lib/servlets-cgi.renametojar file !--to $CATALINA_HOME/server/lib/servlets-cgi.jar But if that is the case, then can someone point me to doc about how I can integrate TC 4 with Apache? The previous versions of TC document this pretty well: http://jakarta.apache.org/tomcat/tomcat-3.3-doc/tomcat-apache-howto.html Where's the equivalent for TC 4? I've seen doc for TC 4 that discusses proxy servers, but I don't know enough to know whether that's the same thing, or something different. Someone help out a flailing newbie here... Jared Paul D. Bain wrote: At Friday 2/22/02 11:58 AM, you wrote: I am not an expert on Tomcat 4, but am 90% sure that it cannot begin execution of any executable program/script other than a servlet/JSP. My understanding (which may be flawed) of this issue is that, if you want to run both Perl and servlets, you must put an Apache web server in front of Tomcat and have it process requests according to whether they invoke Perl files (e.g., the request is for a file whose suffix is .pl) or a servlet (which typically has a different suffix, to wit, .jsp or .java). Apache would process requests for the former via CGI and send requests for the latter to Tomcat. -- To unsubscribe: mailto:[EMAIL PROTECTED] For additional commands: mailto:[EMAIL PROTECTED] Troubles with the list: mailto:[EMAIL PROTECTED]
Tomcat4.0.2 + JNDI jdbc + warp
I've got a very simple servlet that gets a pooled JDBC connection to MySQL that works just fine when I use :8080. When using :80 with an appache warp connection to tomcat, I can't get the connection. I don't know much about JNDI, so that might be the source of my problems. Any and all help is greatly appreciated. Michael Relevant Code: Context initCtx = new InitialContext(); Context envCtx = (Context) initCtx.lookup(java:comp/env); Object ds = envCtx.lookup(jdbc/ResumeDB); ^^^ returns null on :80, but not :8080 WEB-INF/web.xml resource-ref descriptionResource reference for database/description res-ref-namejdbc/ResumeDB/res-ref-name res-typejavax.sql.DataSource/res-type res-authContainer/res-auth /resource-ref conf/server.xml Context path=/resume docBase=resume debug=0 reloadable=true crossContext=true Resource name=jdbc/ResumeDB auth=Container type=javax.sql.DataSource/ ResourceParams name=jdbc/ResumeDB parameter nameuser/name value/value /parameter parameter namepassword/name value/value /parameter parameter namedriverClassName/name valueorg.gjt.mm.mysql.Driver/value /parameter parameter namedriverName/name valuejdbc:mysql://localhost:3306//value /parameter Logger className=org.apache.catalina.logger.FileLogger prefix=localhost_resume_log. suffix=.txt timestamp=true / /Context -- To unsubscribe: mailto:[EMAIL PROTECTED] For additional commands: mailto:[EMAIL PROTECTED] Troubles with the list: mailto:[EMAIL PROTECTED]
mod_webapp on Linux - EAPI?
I downloaded the mod_webapp Linux binary for Tomcat 4.0.1 (I'm actually running 4.0.2 though, if that matters) and installed it. When Apache starts up, I get the warning about needing to re-compile mod_webapp with -DEAPI... Is there a mod_webapp binary available somewhere that has been compiled with the EAPI option? I've tried building it myself... (./support/buildconf.sh followed by ./configure) but when I run configure, I'm getting an error: cannot find or execute './configure' in 'webapp-module-1.0.1-tc401/apr'. Aparently, my Debian unstable system doesn't quite have everything that's needed for this build... So, if I could just download a prebuilt binary from somewhere, it would just be a lot easier. smile Thanks! -Zak -- To unsubscribe: mailto:[EMAIL PROTECTED] For additional commands: mailto:[EMAIL PROTECTED] Troubles with the list: mailto:[EMAIL PROTECTED]
RE: Tomcat 4 and Apache
Hi Kristian, I think I see the problem. you do NOT need the line: AddModule mod_jk.c I have seen this error before and I am no connection geek but I thought this line was not needed for mod_jk and I cchecked with my config and myne does not have it either. Goodluck, brian -Original Message- From: Kristian Duske [mailto:[EMAIL PROTECTED]] Sent: Saturday, February 23, 2002 1:11 PM To: [EMAIL PROTECTED] Subject: Tomcat 4 and Apache Hi everyone, I'm sorry that I'm probably the 100th person to ask this, but I have searched google groups and the archives of this mailing list, both of which failed to help me setting up Tomcat 4.01 with Apache 1.3.23 on Windows. I have tried to load both mod_jk.dll and mod_webapp.so in Apache. mod_jk gives me the following error: Syntax error on line 195 of c:/programme/wamp/apache/conf/httpd.conf: Can't locate API module structure `mod_jk' in file c:/programme/wamp/apache/modules/mod_jk.dll: (127) Die angegebene Prozedur wurde nicht gefunden: The last bit translates to The specified procedure was not found. The relevant lines in my httpd.conf are LoadModule mod_jk modules/mod_jk.dll AddModule mod_jk.c I had more luck with mod_webapp, which loads properly using these lines: LoadModule webapp_module modules/mod_webapp.so AddModule mod_webapp.c WebAppConnection conn warp localhost:8008 But when I add either (or both) of these lines WebAppInfo /webapp-info WebAppDeploy examples conn /examples apache -t gives me the following error: C:\Programme\Wamp\Apacheapache -t Syntax error on line 256 of c:/programme/wamp/apache/conf/httpd.conf: Invalid virtual host name where in line 256 is either one (or the first of) WebAppInfo /webapp-info WebAppDeploy examples conn /examples I have found out that other users had this problem when their ServerName directive was commented out in their httpd.conf, and I have tried that already, without luck. Does anybody have an idea how to solve this problem? Thank you very much Kristian -- To unsubscribe: mailto:[EMAIL PROTECTED] For additional commands: mailto:[EMAIL PROTECTED] Troubles with the list: mailto:[EMAIL PROTECTED] -- To unsubscribe: mailto:[EMAIL PROTECTED] For additional commands: mailto:[EMAIL PROTECTED] Troubles with the list: mailto:[EMAIL PROTECTED]
RE: New bie problem about Tomcat
the service in not supposed to be called at init load time. notice the request response parameters in it. this is called by http get or post don't know why it loads twice.. B -Original Message- From: Krishna Bhamidi [mailto:[EMAIL PROTECTED]] Sent: Saturday, February 23, 2002 11:29 AM To: [EMAIL PROTECTED] Subject: New bie problem about Tomcat Hi, I have a problem about a servlet that I want to start on load of Tomcat. I included into the web.xml for the application under the on-load. The init method of the servlet is called two times, but not the service method of the servlet. I am not sure why the init method should get called 2 times? We are using Tomcat 4.0 on Apache. What do we do to execute a servlet on web-server startup? Krishna. -- To unsubscribe: mailto:[EMAIL PROTECTED] For additional commands: mailto:[EMAIL PROTECTED] Troubles with the list: mailto:[EMAIL PROTECTED]
