Migrating from Log4j 1.x to 2.x involves several steps. Here is a detailed guide on how to do it using Java 11 and Gradle. 1. Update Gradle: If you are using an older version of Gradle, you will need to update it to a version compatible with Log4j 2.x. You can do this by changing the Gradle version in your build.gradle file. 2. Update Log4j Dependency: Update the Log4j dependency in your build.gradle file to the latest version of Log4j 2.x. You can find the latest version on the Log4j website or the Maven Central Repository. 3. Remove Log4j 1.x Dependencies: Remove any Log4j 1.x dependencies from your build.gradle file. The Log4j 2.x library is not compatible with Log4j 1.x libraries, so it is important to remove any conflicting dependencies. 4. Update Log4j Configuration: Migrating to Log4j 2.x may require some changes to your Log4j configuration file. Log4j 2.x uses a different configuration syntax compared to Log4j 1.x. Check the Log4j 2.x documentation for the new configuration syntax and update your configuration file accordingly. 5. Update Logging Code: Log4j 2.x has a different API compared to Log4j 1.x. You will need to update your logging code to use the new Log4j 2.x API. This may involve changing import statements and updating method calls. 6. Resolve Compatibility Issues: Log4j 2.x introduces some changes and deprecations compared to Log4j 1.x. You may encounter compatibility issues with your existing codebase. It is important to carefully review the Log4j 2.x documentation and address any compatibility issues in your code. 7. Test and Debug: After making the necessary changes, thoroughly test your application to ensure that logging functions correctly with Log4j 2.x. Use logging statements to verify that logs are being generated and captured as expected. 8. Update Dependencies: Check the dependencies of your project to ensure they are compatible with Log4j 2.x. Some libraries or frameworks may have specific requirements or compatibility issues with Log4j 2.x. Update any conflicting dependencies to versions that are compatible with Log4j 2.x. 9. Remove Deprecated Code: Log4j 2.x deprecates some classes and methods from Log4j 1.x. It is a good practice to remove any deprecated code from your application and update it to use the new Log4j 2.x classes and methods. 10. Update Documentation: If your application has documentation or user guides, update them to reflect the changes in Log4j version and API. Provide instructions on how to configure and use Log4j 2.x for logging. 11. Deploy and Monitor: Once you are confident that your application is working correctly with Log4j 2.x, deploy it to production. Monitor the logs generated by your application and ensure that they are captured and stored correctly using Log4j 2.x. Migrating from Log4j 1.x to 2.x can be a complex process, especially if your application relies heavily on logging. It is important to thoroughly test your application after the migration to ensure that logging functionality is not affected. Additionally, keep an eye on the Log4j documentation and community for any updates or changes that may impact your application in the future.