There are 9 directories under Tomcat: **bin**, **common**, **conf**, **logs**, **server**, **shared**, **temp**, **webapps**, and **work**. Below is an introduction to each directory:
1. **bin**: This directory contains the startup and shutdown scripts for Tomcat, as well as other executable files. It includes scripts such as `startup.bat`/`startup.sh` (for starting Tomcat) and `shutdown.bat`/`shutdown.sh` (for stopping Tomcat). These scripts manage the lifecycle of the Tomcat server.
2. **common**: In older versions of Tomcat, this directory was used to store JAR files that were shared between the server and all web applications. However, in newer versions of Tomcat, this structure has been replaced by more specific classloading mechanisms.
3. **conf**: This directory contains configuration files for Tomcat, including the main configuration file `server.xml`, which defines global settings, connectors, and contexts. Other important files include `web.xml` (default servlet configurations), `context.xml` (context-specific configurations), and `tomcat-users.xml` (user roles and credentials).
4. **logs**: This directory stores log files generated by Tomcat during runtime. The most common log file is `catalina.out`, which contains general logging information and error messages. Additional logs may be created depending on the application's logging configuration.
5. **server**: Similar to the `common` directory, this directory was used in older versions of Tomcat to store JAR files specific to the server itself, not shared with web applications. In newer versions, this directory has been deprecated or restructured.
6. **shared**: This directory was used in older versions of Tomcat to store JAR files that were shared among all web applications but not part of the core server. In newer versions, this functionality has been replaced by better classloading mechanisms.
7. **temp**: This directory is used by Tomcat as a temporary storage location during runtime. For example, it may store temporary files created by web applications or during the execution of certain processes.
8. **webapps**: This is the default deployment directory for web applications. When you deploy a WAR file or an unpacked web application, it is typically placed in this directory. Tomcat automatically detects and deploys applications from this folder.
9. **work**: This directory is used by Tomcat to store compiled Java files and other temporary work files during the execution of JSP pages or other dynamic content. Once the server is restarted or the application is redeployed, the contents of this directory may be cleared.
These directories collectively define the structure and functionality of the Tomcat server, allowing developers to configure, deploy, and manage web applications effectively.