Before you switch DNS or point users to the new host, a migrated JSP application should be checked in the same way you would test any Java web app after deployment: confirm that the Tomcat service starts, the correct Java version is active, the application responds through its public URL, and the main business flows still work. In a hosting control panel environment, especially when using a private JVM and Apache Tomcat through Plesk, the goal is not only to see that the site opens, but to verify that the full stack is behaving as expected after migration.
This checklist is designed for JSP hosting, Tomcat hosting, and servlet-based applications that have been moved to a new hosting account and need final validation before going live. It works well for applications running on a managed hosting platform with a control panel such as Plesk and a Java service managed through a tool like My App Server.
What to verify before go-live
A migration can look successful at first glance even when there are hidden issues. A JSP application may load its home page correctly, but still fail on form submissions, file uploads, session handling, database calls, or background tasks. Before releasing the application to users, confirm the following areas:
- The Tomcat or custom app server service starts without errors.
- The correct Java version is installed and selected.
- The application deploys cleanly from WAR, exploded directory, or custom deployment path.
- All key pages, forms, and login flows work.
- Database connectivity is valid and uses the expected credentials.
- Static assets, JSP pages, and servlet mappings respond correctly.
- SSL, redirects, and canonical URLs behave as intended.
- Logs are clean enough to indicate a stable launch.
If your application uses a private JVM or custom Tomcat instance inside a hosting account, testing should also confirm that the service controls in the panel are working and that restart behavior is reliable.
Confirm the application server is running correctly
Check service status in the control panel
After migration, the first step is to verify that the Java service is running. In a Plesk-based environment with My App Server, open the service control area and confirm that the application server is active. If the service is stopped, start it and watch for startup errors.
Look for common indicators such as:
- Tomcat started successfully.
- The JVM launched with the expected memory settings.
- No port binding conflicts are reported.
- No missing file or permission errors appear during startup.
If the service fails to start, inspect the logs before testing the application itself. A page that opens through cache or an old DNS path may hide a startup problem for a short time, so service verification should always come first.
Verify the Java version
One of the most common migration problems is running the application on a different Java version than the one used on the old host. This can affect class loading, annotation scanning, TLS behavior, date/time handling, and framework compatibility.
Check that:
- The installed Java version matches the application requirement.
- The selected runtime for the Tomcat instance is the intended one.
- No unsupported newer or older version is being used accidentally.
If your application depended on a specific JDK or JRE level before migration, make sure the same level is chosen in the hosting platform. Even minor version differences can matter for older JSP applications.
Test the deployment path and application access
Open the application using the test URL
Before changing DNS, use the temporary URL, internal host name, or preview address provided by the hosting platform if available. This lets you test the migrated site without exposing users to an unfinished setup.
When opening the application, confirm that:
- The correct context path loads.
- There are no 404 or 500 errors on the main page.
- JSP pages compile and render properly.
- Servlet routes resolve as expected.
If the app uses a custom context root, verify that it matches the deployed directory or WAR name. A mismatch here can break links, session routes, and redirects.
Check static and dynamic resources
Many JSP applications rely on a mix of JSP files, servlets, images, CSS, JavaScript, and uploaded content. After migration, test that all resource types load correctly.
Review:
- Stylesheets and scripts.
- Images and icons.
- Download links.
- AJAX calls and JSON responses.
- Uploaded media or user-generated files, if applicable.
Broken paths often appear after a migration because absolute URLs, old server aliases, or hardcoded file paths were left unchanged. This is especially important for applications that were not built with portable deployment in mind.
Validate JSP compilation and servlet behavior
Open every major JSP section
Do not test only the homepage. JSP applications often have sections that compile lazily, meaning an error might appear only when a specific page is opened for the first time. Visit the most important JSP pages, including admin areas, search pages, profile pages, checkout or submission pages, and any page that includes custom tags or server-side includes.
Watch for:
- Compilation errors in JSP files.
- Missing tag libraries.
- Class not found errors.
- Encoding or character set issues.
- Template include failures.
If the migration changed file ownership, permissions, or deployment layout, JSP compilation may fail even if the source code is intact.
Test servlet mappings and filters
Servlet-based applications should be checked for correct URL mapping. Open each important servlet endpoint and verify that it returns the expected response. If the application uses filters for authentication, compression, logging, or request rewriting, confirm that they are active and not blocking valid requests.
Common issues to look for include:
- Incorrect web.xml mappings.
- Broken path parameters.
- Filter chains that fail after migration.
- Different behavior between direct JSP access and servlet access.
Check database connectivity and data consistency
For most JSP applications, the database is one of the most sensitive parts of a migration. Even when the application server works, database access can fail because of wrong credentials, changed hostnames, driver differences, or network access restrictions.
Run the main database-dependent workflows
Test the application features that read and write data:
- Log in and authentication flows.
- Search and filter functions.
- Record creation and edits.
- Form submission and confirmation pages.
- Order, ticket, or content processing flows.
Confirm that the application can connect to the database using the same driver version and connection string expected by the app. If the old environment used a local database and the new one uses a remote service, latency and timeout settings may need adjustment.
Review transaction and error handling
Test a few invalid actions as well, such as submitting incomplete forms or entering wrong credentials. Good validation helps you confirm that the application is not only connecting to the database but also handling failures in a controlled way.
Look at whether error pages are user-friendly and whether internal exceptions are logged correctly rather than shown to visitors.
Verify sessions, cookies, and authentication
After a migration, session problems are common because of changes in domain, SSL, cookie scope, timeout settings, or Tomcat session configuration. This can make the site appear functional but break login persistence or shopping cart behavior.
Test login and logout flows
Complete a full user session test:
- Log in with a valid account.
- Navigate through several protected pages.
- Log out and log in again.
- Leave the session idle long enough to trigger timeout behavior.
Check whether the application:
- Maintains the session correctly.
- Honors secure cookie settings over HTTPS.
- Redirects to the expected page after login.
- Does not lose state after refresh or back navigation.
Check cookie scope and domain behavior
If the migrated application is moving to a new domain, subdomain, or HTTPS-only setup, verify that cookies are issued with the proper domain and path. A cookie that was valid on the old host may not work correctly after the migration if the scope is too narrow or too broad.
Test file uploads, downloads, and permissions
Validate upload functionality
Java web apps often handle file uploads through servlet-based components or third-party libraries. Migration can expose permission issues in upload directories, temporary folders, or storage paths.
Upload a few test files and confirm that:
- The files are accepted successfully.
- The content type and file size rules work.
- The files are stored in the expected location.
- Uploaded files can be viewed or downloaded afterward.
Check file system paths
Applications migrated to a new hosting account may still reference old absolute paths from the previous environment. Review path-dependent features such as:
- Export directories.
- Image storage locations.
- Report generation folders.
- Temporary directories used by Tomcat or the application.
Where possible, use relative paths or configuration values stored in the hosting control panel or application properties rather than hardcoded server paths.
Review SSL, redirects, and URL consistency
Before going live, make sure the public-facing URL behavior is correct. This is particularly important if the application will be launched over HTTPS and if old bookmarks or search engine indexing need to be redirected properly.
Check HTTPS access
Open the application over HTTPS and verify that:
- The certificate is valid.
- There are no mixed content warnings.
- Login forms and sensitive pages remain secure.
- All internal links continue to use the correct protocol.
If the application generates absolute links, confirm that they point to the final production domain and not the temporary migration host.
Test redirects and canonical links
Confirm that old URLs redirect as intended, especially if the site structure changed during migration. Redirect tests should cover:
- HTTP to HTTPS.
- Non-www to www or the reverse, if applicable.
- Old context paths to the new application path.
- Legacy URLs used in bookmarks or external references.
Incorrect redirect rules can create loops or send visitors to the wrong version of the site. Always test them before DNS cutover.
Inspect logs for hidden migration problems
Application logs and server logs are one of the best ways to confirm whether the migrated JSP app is truly ready. A page may appear to work even while warnings, deprecations, or failed background processes are being recorded.
What to look for in logs
Review the Tomcat and application logs for:
- JSP compilation warnings.
- Class loading errors.
- Database connection failures.
- File permission problems.
- Out-of-memory warnings or thread pool issues.
- Stack traces repeated across multiple requests.
If your hosting platform provides service control and log access in the control panel, use those tools directly after each test step. This helps you identify whether a problem came from the server, the application code, or the migration process itself.
Run performance and stability checks
A small or medium JSP application does not need heavy enterprise load testing to validate a migration, but you should still perform basic performance checks. The goal is to see whether the new environment responds normally under expected usage.
Measure page response times
Open the most important pages a few times and note how long they take to load. The first request may be slower because JSPs are compiled on demand, but repeated requests should be stable. Large differences between pages can reveal missing caching, slow database queries, or resource loading issues.
Restart the service and retest
Restarting the Tomcat service is a useful validation step. It confirms that the application starts cleanly and that startup order, deployment, and configuration are consistent. After restart, repeat the main checks:
- Home page loads.
- Login works.
- Database-dependent pages work.
- Static resources still load.
This is especially relevant when using a private JVM or a custom Tomcat setup in a hosting account, because service-level control is part of the actual production behavior.
Final go-live checklist for migrated JSP applications
Use this compact checklist before switching traffic to the new hosting environment:
- Tomcat or the custom Java app server starts successfully.
- The correct Java version is active.
- The application opens from the test URL.
- JSP pages compile and render properly.
- Servlet routes and filters work as expected.
- Login, session, and logout flows are stable.
- Database reads and writes succeed.
- File uploads and downloads work.
- HTTPS and redirects are correct.
- Logs show no critical errors.
- A restart test completed without problems.
If all items pass, the application is usually ready for DNS cutover or final URL switch.
Common problems after migration
JSP compilation errors
These are often caused by missing libraries, wrong Java version, or changed file permissions.
Session loss after login
Usually related to cookie settings, incorrect domain handling, or HTTPS changes.
500 errors on specific pages
Often caused by missing configuration files, database connection issues, or a dependency that was not copied during migration.
Static assets not loading
This usually points to hardcoded paths, incorrect context root settings, or permission problems in resource folders.
Service starts but the application is not reachable
Check port configuration, deployment location, context path, and whether the application actually finished loading inside Tomcat.
FAQ
Should I test the application before changing DNS?
Yes. Always test on a temporary URL, preview link, or direct host mapping first so you can catch errors without impacting users.
What is the most important thing to check after migrating a JSP app?
Start with the Java service, then test the core business flows: login, database access, and key JSP or servlet pages. These reveal most migration issues quickly.
Why does the homepage work but some pages fail?
Some JSP pages compile or execute only when they are visited. A migration can look successful at first while specific routes still have dependency or configuration issues.
Do I need to restart Tomcat after migration?
Yes, a restart test is strongly recommended. It confirms that the application can start cleanly and that its configuration is stable in the new environment.
How do I know if the Java version is correct?
Compare the version used by the application with the one selected in the hosting control panel. If the app requires a specific Java release, use that exact version or a compatible one.
What if I find errors in the logs but the site seems fine?
Do not ignore them. Repeated warnings or stack traces can indicate a hidden issue that will surface under real user traffic.
Conclusion
Testing a migrated JSP application before going live is about more than opening the homepage. A reliable final check includes the Java runtime, Tomcat service status, JSP compilation, servlet routing, database access, session handling, file operations, SSL behavior, and logs. In a hosting platform with Plesk and a managed Java service such as My App Server, these checks are practical to perform and give you a clear picture of whether the migration is ready for production traffic.
Once the application passes these validations, you can move forward with confidence, knowing that the migrated JSP site is functioning correctly in its new hosting environment.