WARN o.eclipse.jetty.webapp.WebAppContext – Failed startup of context ** java.lang.IllegalStateException: The application Lookup instance is not found in VaadinContext. The instance is suppoed to be created by a ServletContainerInitializer.

The error message you’ve provided seems to be related to the startup of a web application using the Jetty web server and the Vaadin framework. This error message indicates that there’s an issue with the initialization of a Vaadin application within a Jetty server context. Here’s a breakdown of what the error message is conveying:

1. java.lang.IllegalStateException: This is a Java exception indicating that an illegal state has been reached during the execution of the program. In this case, something unexpected has occurred during the startup process.
2. The application Lookup instance is not found in VaadinContext: This part of the error message suggests that there is a specific instance or component called “Lookup” that is expected to be available in the Vaadin context, but it cannot be found.
3. The instance is supposed to be created by a ServletContainerInitializer: This indicates that the “Lookup” instance is expected to be created by a class that implements the ServletContainerInitializer interface. This interface is part of the Java Servlet API and is used for initializing web applications within a Servlet container, like Jetty.

It seems that the problem might be related to the configuration or initialization of your Vaadin application within the Jetty web server. Here are some steps you can take to troubleshoot and resolve the issue:

1. Check Your Dependencies: Make sure you have the correct versions of the Vaadin framework and any related libraries in your project’s dependencies. Mismatched or incompatible versions could lead to initialization issues.
2. Check Initialization Code: Look at your code where you configure and initialize the Vaadin application. Ensure that you are properly initializing the Vaadin context and any required components. The error message suggests that the “Lookup” instance is missing, so make sure you are creating and configuring it correctly.
3. ServletContainerInitializer: Since the error message mentions that the “Lookup” instance is supposed to be created by a ServletContainerInitializer, review any code related to this initialization process. Make sure that the initializer is correctly registered and executed during the startup of the Jetty server.
4. Logging and Debugging: Increase the logging level for your application and Jetty server to get more detailed information about what’s happening during startup. This could help you pinpoint the exact location or step where the error is occurring.
5. Consult Documentation and Community: Check the official documentation of Vaadin and Jetty for any specific guidance on deploying Vaadin applications to Jetty. You can also search online forums and communities for similar issues that others may have faced.
6. Testing on Different Environments: If possible, try deploying your application on different environments or servers to see if the issue is specific to the current setup.

Remember to carefully review your code and configuration to identify any potential issues that could be causing the error. If you’re unable to resolve the problem, providing more details about your setup, code snippets, and any relevant configuration could help others provide more specific assistance.