Spring Boot is a powerful framework that simplifies the process of developing stand-alone, production-grade Spring applications. However, developers sometimes encounter issues with older elements of the Spring ecosystem, such as SpringApplicationConfiguration . An error message such as "SpringApplicationConfiguration not found" typically occurs when there's an issue originating from deprecated or erroneous content in the spring-boot-starter-test . This article dives into the potential causes and solutions related to this problem.

Understanding the Error

The SpringApplicationConfiguration was an annotation used in earlier versions of Spring Boot to load a Spring application context for integration tests. With the introduction of Spring Boot 1.4, it was replaced by @SpringBootTest . If you encounter a "not found" error, it is likely because the code is trying to use this deprecated annotation with a newer version of Spring Boot that no longer supports it.

Deprecated Elements

Here’s what typically leads to the SpringApplicationConfiguration not found error:

1. Using newer Spring Boot versions: If you are using Spring Boot 1.4 or later, ensure that all obsolete annotations like SpringApplicationConfiguration are removed.
2. Inconsistent versions: Check the dependencies in your pom.xml or Gradle build.gradle file to ensure that the versions of Spring Boot and Spring Framework are compatible.
3. Outdated documentation or tutorials: Follow newer documentation when learning or setting up a project to avoid implementing outdated patterns.

Solutions

Updating to @SpringBootTest

The modern way to write integration tests in a Spring Boot application is by using the @SpringBootTest annotation.

Here's an example of how to modify a test class to replace SpringApplicationConfiguration with @SpringBootTest :

• Spring Boot's BOM (Bill of Materials): Utilize BOM to manage compatibility between dependencies.
• Regular Library Updates: Regularly update your libraries to ride on performance enhancements and bug fixes.
• Unit and Integration Tests: Separate unit tests and integration tests configure them properly using profiles or separate test execution phases.