Apache Tomcat is an open-source web server and Servlet container for Java code. It’s a production-ready Java development tool used to implement many types of Jakarta EE (formerly known as Java EE) specifications. Apache Tomcat 10.1.18 is the current Tomcat release and is still undergoing active development.
The "Logging" tab in tomcat8w.exe is specifically designed to control the logging behavior of the Tomcat Windows Service itself, not the logging of the web applications deployed within Tomcat. Think of it as managing the logs related to the service wrapper that allows Tomcat to run as a Windows service.
tomcat8w.exe

* **NOT Web Application Logging:** It’s crucial to understand that this tab **does not control the logging of your web applications**. Web application logging is typically configured within the Tomcat server (using `logging. Properties` or a framework like Log4j/Logback within your application) or through the application itself.
Accessing the Logging Tab:
- Locate and Run
tomcat8w.exe
:
- This executable is usually located in the
bin
directory of your Tomcat installation (e.g.,C:\Program Files\Apache Software Foundation\Tomcat 8.5\bin
). - You might see variations like
tomcat9w.exe
for Tomcat 9, etc. - Important: You need to run
tomcat8w.exe
as an administrator. Right-click on it and select “Run as administrator.”
- Select Your Service:
- If you have multiple Tomcat instances installed, a window will pop up asking you to select the service you want to configure. Choose the appropriate service and click “OK.”
- Navigate to the “Logging” Tab:
- The Tomcat Properties window will appear. Click on the “Logging” tab.
Understanding the Logging Tab Options:
The Logging tab typically provides settings for controlling logging output, redirection, and levels. Here’s a common layout and explanation of the options:
- Log path: This field specifies the directory where your log files will be stored.
- Example:
C:\Program Files\Apache Software Foundation\Tomcat 8.5\logs
- Default: Usually the
logs
directory within your Tomcat installation.
- Example:
- Prefix: This sets the prefix for your log file names. Tomcat typically uses the following:
catalina
: For general Tomcat engine logs.localhost
: For logs related to the default host.manager
: For logs of the Manager application.host-manager
: For logs of the Host Manager application.localhost_access_log
: For access logs.- Example:
catalina
(which might result in a file likecatalina.2023-10-27.log
).
- Suffix: This is the extension for the log files.
- Example:
.log
(usually the default).
- Example:
- Timestamp: This checkbox determines whether to include a timestamp in the log file names. It’s typically enabled by default, and it is highly recommended to keep it enabled.
- When enabled, a date will be added between the prefix and the suffix, like
catalina.2023-10-27.log
.
- When enabled, a date will be added between the prefix and the suffix, like
- Stdout (Standard Output):
- Redirect: This controls where the standard output (stdout) stream is directed.
- Blank: Output will typically go to the console or system logs, depending on how Tomcat is running.
- Example to redirect to a file:
C:\Program Files\Apache Software Foundation\Tomcat 8.5\logs\stdout.log
auto
: the output will be written into a file named<prefix>.<current-date>.stdout
in the logging directory.
- Level: This option typically isn’t available on the Logging tab but might be found elsewhere or adjusted through configuration files. It sets the logging level for stdout (e.g., INFO, DEBUG, ERROR).
- Redirect: This controls where the standard output (stdout) stream is directed.
- Stderr (Standard Error):
- Redirect: Controls where the standard error (stderr) stream is directed.
- Blank: Output will typically go to the console or system logs.
- Example to redirect to a file:
C:\Program Files\Apache Software Foundation\Tomcat 8.5\logs\stderr.log
auto
: the output will be written into a file named<prefix>.<current-date>.stderr
in the logging directory.
- Level: Similar to stdout, this option is often managed separately and controls the logging level for stderr.
- Redirect: Controls where the standard error (stderr) stream is directed.
- Level: This dropdown is the key setting for controlling the verbosity of your logs. The common logging levels are (from most to least verbose):
- ALL: Logs everything.
- FINEST: Extremely detailed, very granular messages.
- FINER: More detailed than FINE.
- FINE: Detailed debugging information.
- CONFIG: Configuration messages.
- INFO: Informational messages.
- WARNING: Potential problems or issues.
- SEVERE: Serious errors.
- OFF: Turns logging off.
- Recommendation:
INFO
is generally a good starting point. UseFINE
orFINER
for debugging specific issues but revert toINFO
afterward to avoid overwhelming the logs.
How to Use and Make Changes:
- Adjust Settings: Modify the
Log path
,Prefix
,Suffix
,Stdout
,Stderr
, andLevel
options as needed. - Apply and Restart:
- Click the “Apply” button to save your changes.
- Click the “OK” button to close the window.
- Important: For most logging changes to take effect, you usually need to restart the Tomcat service. You can do this either through the “General” tab of
tomcat8w.exe
(click “Stop,” then “Start”) or through the Windows Services console.
Important Considerations:
logging.properties
: While thetomcat8w.exe
Logging tab provides a convenient interface for basic logging configuration, Tomcat’s full logging capabilities are controlled by thelogging.properties
file located in theconf
directory. This file offers more advanced options like configuring different log handlers, formatters, etc. If you need finer-grained control or more complex configurations, you might need to directly editlogging.properties
.- Log Rotation: The
tomcat8w.exe
logging tab does not handle log rotation. With timestamp enabled, the date will be part of the log filename. Tomcat will not delete old logs, so make sure to implement a log rotation strategy (e.g., using tools likelogrotate
on Linux or a scheduled task on Windows) to prevent log files from consuming excessive disk space. - Performance: Excessive logging can impact performance. Always choose an appropriate logging level based on your needs. Avoid using levels like
FINEST
orALL
in production environments unless you are actively debugging a specific problem. - Security: Be mindful of what you log. Avoid logging sensitive information like passwords, credit card numbers, or other confidential data.
By using the Logging tab in tomcat8w.exe
effectively, you can manage the essential logging settings of your Tomcat instance, monitor its operation, and troubleshoot issues more easily. Remember to balance verbosity with performance and security considerations.
\temp
Files named upload_date.tmp
(where date
represents a timestamp) in Tomcat’s temp
directory are almost certainly temporary files created during file uploads by a web application deployed on that Tomcat server. The exact contents and behavior depend entirely on the application itself and how it handles file uploads. Let’s break down the likely scenario:
- The Upload Process: When a user uploads a file through a web form (or via an API), the application receives the file data as a stream. Instead of directly saving the file to its final destination, many applications create a temporary file first to store the uploaded data. This temporary file acts as a buffer, allowing the application to verify the upload, perform checks (like file size limits, allowed file types), and potentially process the file before moving it to its permanent location.
upload_date.tmp
Naming: Theupload_date.tmp
naming convention is a common, though not universally used, approach. The “upload” prefix clearly indicates the file’s origin, and the timestamp ensures uniqueness, preventing overwriting of temporary files from concurrent uploads.- Cleanup: A well-written application will delete these temporary files once the upload process is complete (successfully or unsuccessfully). If the upload succeeds, the temporary file is typically moved or renamed to its final location. If the upload fails (e.g., due to an error, exceeding size limits, or an invalid file type), the temporary file should be deleted.
- Potential Problems: The presence of many
upload_date.tmp
files suggests one of the following:- Incomplete Uploads: The application might have experienced errors during uploads, leaving behind numerous temporary files. This could be due to network issues, server problems, or bugs in the application’s upload handling code.
- Lack of Cleanup: The application might have a flaw in its code that prevents the proper deletion of temporary files after the upload. This can lead to a buildup of these files, consuming disk space and potentially causing performance issues.
- High Upload Volume: A large number of files might simply reflect a high volume of uploads to the application. While not necessarily a problem, it’s worth investigating if the disk space usage is becoming concerning.
How to Investigate:
- Identify the Application: Determine which web application is responsible for these uploads. Examine the Tomcat logs (usually in the
logs
directory) for clues. Error messages related to file uploads or exceptions might pinpoint the culprit. - Examine the Application Code: If you have access to the application’s source code, review the parts that handle file uploads. Look for potential issues in the code that might prevent proper cleanup of temporary files.
- Check for Errors: Look for errors in the Tomcat logs related to file uploads. These logs might provide insights into why uploads are failing or why the temporary files aren’t being deleted.
- Monitor Disk Space: Keep an eye on the disk space usage in the
temp
directory. If it continues to grow rapidly, it indicates a serious problem that needs to be addressed.
In short, while upload_date.tmp
files are expected during file uploads, a large number indicates a problem within the application’s upload handling mechanism. Investigating the application’s code and logs is crucial to identify and resolve the root cause.