Worked on the aws/serverless-java-container repository to enhance the reliability and startup performance of Java serverless applications on AWS. Addressed a critical initialization issue in Spring Boot by updating the SpringApplicationBuilder to include the main class and replacing the context class with ConfigurableWebApplicationContext, which improved cold start times and reduced startup errors. Further strengthened the project by developing targeted unit tests for the SpringBootLambdaContainerHandler, using Java and Mockito to validate initialization paths and ensure robust deployment in Lambda environments. Demonstrated a disciplined approach to testing and maintainability, focusing on Spring Boot, serverless architecture, and comprehensive unit test coverage.