Java.lang.illegalstateexception: failed to execute commandlinerunner

java.lang.IllegalStateException: Failed to execute CommandLineRunner

The exception java.lang.IllegalStateException is thrown when there is an illegal or inappropriate attempt to execute a command line runner in a Spring Boot application.

Possible Causes:

1. No CommandLineRunner Implementation: Ensure that you have implemented the CommandLineRunner interface in your Spring Boot application. CommandLineRunner provides a callback interface that allows your code to be executed after the application context has been loaded and before the application is started.

   Example:

           
           import org.springframework.boot.CommandLineRunner;
   
           public class MyCommandLineRunner implements CommandLineRunner {
           
               @Override
               public void run(String... args) throws Exception {
                   // Your code here
               }
           }
           
           

2. Incorrect Bean Configuration: Ensure that the CommandLineRunner bean is properly configured in your application context. This can be achieved using annotations like @Component or @Bean. If the bean is not correctly configured, Spring Boot may fail to execute the command line runner.

   Example:

           
           import org.springframework.stereotype.Component;
   
           @Component
           public class MyCommandLineRunner implements CommandLineRunner {
           
               @Override
               public void run(String... args) throws Exception {
                   // Your code here
               }
           }
           
           

3. Dependency Issues: Make sure all the required dependencies for your command line runner are properly declared in your application’s build file (e.g., pom.xml for Maven). Any missing or incompatible dependencies can cause the command line runner to fail during execution.

Additional Tips:

• Check the application logs for more detailed error messages. The logs can provide further insights into the cause of the exception.
• Ensure that all the necessary configurations and dependencies are properly set up for your Spring Boot application. Refer to the official Spring Boot documentation for guidance.

By addressing the possible causes mentioned above and following the best practices for implementing and configuring the command line runner, you should be able to resolve the java.lang.IllegalStateException: Failed to execute CommandLineRunner exception in your Spring Boot application successfully.