How to Resolve "Error Starting ApplicationContext" in Spring Boot: A Personal Experience

If you've ever run into the dreaded “Error starting ApplicationContext. To display the condition evaluation report, re-run your application with ‘debug’ enabled.” message in a Spring Boot application, you know the frustration. Trust me, I’ve been there, and I understand how confusing it can be. But don't worry—I've got you covered with practical solutions that work.

This error generally occurs when Spring Boot fails to start due to an issue in the application context configuration. It might sound complicated, but let’s break it down step-by-step and explore how you can fix it.

Understanding the Error

At its core, this error indicates that Spring Boot has encountered a problem while trying to load the ApplicationContext. The ApplicationContext is like the heart of your Spring Boot application—it manages beans, configurations, and everything else needed to run your app smoothly. When this process fails, Spring doesn’t know how to proceed, so it throws this error.

Why Does This Happen?

Based on my research and personal experience, here are the most common reasons for this error:

  • Missing or Incorrect Bean Configuration: If you have a bean that is not properly configured, Spring Boot won't know how to handle it.
  • Profile-Specific Configurations: If you are using profiles (e.g., dev, prod), ensure the correct profile is being loaded.
  • Dependencies Not Met: Sometimes Spring Boot expects a certain dependency (like a database or service), and if that isn’t configured properly, it will fail.
  • Circular Dependencies: Circular dependencies in bean declarations can also cause the application context to fail.

Solution 1: Enable Debug Mode

The first step is to re-run the application with ‘debug’ enabled to get more information. This will give you a detailed report of what's going wrong in the application context. To enable debug mode, you can add the following to your application.properties or application.yml file:

logging.level.org.springframework.boot.autoconfigure=DEBUG

Alternatively, you can pass the --debug flag when running your application:

./mvnw spring-boot:run --debug

This detailed log will point you to the exact issue—whether it’s a bean misconfiguration or a missing dependency.

Solution 2: Check Your Bean Configuration

Often, the problem lies with misconfigured beans. If a bean isn't correctly defined or is missing required dependencies, the ApplicationContext won’t load.

  • Review your configuration files (@Configuration, @Bean, @Component, etc.) to ensure that all beans are properly defined.
  • Ensure you’re not missing any required dependencies. For example, if you’re using JPA, make sure your EntityManager is correctly set up.

For example, I once forgot to declare a bean for a service class, which caused the ApplicationContext to fail. Once I added the missing @Bean annotation, everything worked perfectly.

Solution 3: Use the Right Profile

If you're using profiles (e.g., dev, prod), make sure you’ve specified the right profile for your environment. You can set the active profile in your application.properties file like this:

spring.profiles.active=dev

I’ve had instances where the wrong profile was loaded, leading to missing configurations and ultimately causing the ApplicationContext to fail.