Java.lang.illegalstateexception: failed to execute commandlinerunner

When the java.lang.IllegalStateException: Failed to execute CommandLineRunner exception is thrown, it means that something went wrong while executing a command-line runner in a Spring Boot application. The CommandLineRunner interface in Spring Boot allows you to define a callback method that will be automatically invoked during the application startup.

This exception usually occurs due to the following reasons:

1. Missing required dependencies: If the command-line runner depends on some other components or beans that are not correctly defined or not present, this exception may be thrown. Make sure all the necessary dependencies are properly configured.
   
   Example:

           public class MyCommandLineRunner implements CommandLineRunner {
             
             private MyService myService;
             
             public MyCommandLineRunner(MyService myService) {
               this.myService = myService;
             }
             
             public void run(String... args) {
               myService.doSomething();
             }
           }
           
           // Missing configuration for MyService
         

2. Dependency injection failure: If there is an issue with dependency injection, such as circular dependencies or ambiguous bean definitions, the CommandLineRunner may fail to execute. Check your bean configurations and ensure there are no conflicts or circular references.
   
   Example:

           public class MyCommandLineRunner implements CommandLineRunner {
             
             private MyServiceA serviceA;
             private MyServiceB serviceB;
             
             public MyCommandLineRunner(MyServiceA serviceA, MyServiceB serviceB) {
               this.serviceA = serviceA;
               this.serviceB = serviceB;
             }
             
             public void run(String... args) {
               serviceA.doSomething();
               serviceB.doSomething();
             }
           }
           
           // Circular dependency between MyServiceA and MyServiceB
         

3. Error in the command-line runner code: If there is an exception or error occurring within the code of the command-line runner itself, it can result in the failure to execute. Examine the code within the CommandLineRunner implementation for any possible issues or errors.
   
   Example:

           public class MyCommandLineRunner implements CommandLineRunner {
             
             public void run(String... args) {
               int result = 10 / 0; // ArithmeticException
             }
           }
           
           // Incorrect calculation results in ArithmeticException
         

To resolve the java.lang.IllegalStateException: Failed to execute CommandLineRunner exception, you need to debug and identify the specific cause based on the above possible reasons. Once identified, modify and rectify the corresponding code or configuration to fix the issue.