Failed to instantiate webapplicationinitializer class

Failed to Instantiate WebApplicationInitializer Class

When you encounter the error message “Failed to instantiate WebApplicationInitializer class”, it usually means that the web server is unable to instantiate the specified class that implements the WebApplicationInitializer interface or one of its dependencies. The WebApplicationInitializer is a key interface from the Spring Framework and is responsible for bootstrapping a web application context.

This error can occur due to various reasons such as:

The class or its dependencies are not in the classpath.
The class does not have a no-argument constructor.
The class is not implementing the WebApplicationInitializer interface correctly.

Example: Invalid Implementation of WebApplicationInitializer

Let’s consider an example where we have a class named MyWebAppInitializer that is supposed to be the main entry point for our web application. It should implement the WebApplicationInitializer interface. However, due to an error, it fails to do so correctly.


import org.springframework.web.servlet.support.AbstractAnnotationConfigDispatcherServletInitializer;

public class MyWebAppInitializer extends AbstractAnnotationConfigDispatcherServletInitializer {

  // Missing implementation of WebApplicationInitializer methods

}

In the above example, MyWebAppInitializer extends AbstractAnnotationConfigDispatcherServletInitializer, which in turn implements WebApplicationInitializer. However, the MyWebAppInitializer class is missing the required implementation of the abstract methods defined by the WebApplicationInitializer interface.

Solution: Correcting the Implementation

To fix this error, you need to provide the correct implementation of the WebApplicationInitializer interface. Ensure that you override the necessary methods and provide the required configurations. Here’s an updated version of the previous example:


import org.springframework.web.servlet.support.AbstractAnnotationConfigDispatcherServletInitializer;

public class MyWebAppInitializer extends AbstractAnnotationConfigDispatcherServletInitializer {

  @Override
  protected Class[] getRootConfigClasses() {
    return null;
  }

  @Override
  protected Class[] getServletConfigClasses() {
    return new Class[]{AppConfig.class};
  }

  @Override
  protected String[] getServletMappings() {
    return new String[]{"/"};
  }
}

In the corrected implementation, we have overridden the necessary methods – getRootConfigClasses(), getServletConfigClasses(), and getServletMappings(). These methods provide the necessary configurations for our Spring web application. Make sure to replace AppConfig.class with your own configuration class or provide separate implementations for these methods based on your project’s requirements.

After making the necessary corrections, recompile and redeploy your application. The error “Failed to instantiate WebApplicationInitializer class” should no longer occur if you have provided the correct implementation and ensured the dependencies are correctly set up.

Failed to instantiate webapplicationinitializer class