2 spring webapplicationinitializers detected on classpath

2 Spring WebApplicationInitializers Detected on Classpath

When you encounter the message “2 Spring WebApplicationInitializers Detected on Classpath,” it means that there are two classes implementing the WebApplicationInitializer interface in your Spring web application. The WebApplicationInitializer is an interface provided by Spring that allows you to configure the ServletContext programmatically.

Explanation

In a Spring web application, the initialization of the application is handled by a class that implements the WebApplicationInitializer interface. This class is responsible for setting up the ServletContext, registering servlets, filters, and listeners, and configuring other aspects of the application.

The message “2 Spring WebApplicationInitializers Detected on Classpath” suggests that there are two classes implementing the WebApplicationInitializer interface, which can lead to unexpected behavior during application startup. Normally, there should be only one class implementing this interface in your application.

Example

Let’s consider an example where you have two classes implementing the WebApplicationInitializer interface:

    
    public class MyWebApplicationInitializer1 implements WebApplicationInitializer {
      public void onStartup(ServletContext servletContext) throws ServletException {
        // Configuration and initialization code
      }
    }

    public class MyWebApplicationInitializer2 implements WebApplicationInitializer {
      public void onStartup(ServletContext servletContext) throws ServletException {
        // Configuration and initialization code
      }
    }

In this example, both MyWebApplicationInitializer1 and MyWebApplicationInitializer2 implement the WebApplicationInitializer interface. During the application startup, the onStartup method of both classes will be invoked, potentially causing conflicts or duplicated configuration.

Solution

To resolve this conflict, you should ensure that there is only one class implementing the WebApplicationInitializer interface. You can either remove one of the classes or merge their functionality into a single class.

For example, you can have a single class that implements the WebApplicationInitializer interface and contains the combined configuration from both initializers:

    
    public class MyWebApplicationInitializer implements WebApplicationInitializer {
      public void onStartup(ServletContext servletContext) throws ServletException {
        // Configuration and initialization code from both initializers
      }
    }

With this approach, you have a single WebApplicationInitializer class that handles the configuration and initialization of your application.

Note that there can be cases where having multiple initializers is intentional, like when working with modularized applications. However, it’s crucial to ensure that the initialization logic of each initializer does not conflict with others.

2 spring webapplicationinitializers detected on classpath