Worked on the Activiti/activiti-cloud repository to enhance security observability by addressing authentication token validation. Focused on backend development using Java, the work involved updating the JwtAccessTokenValidator and ExpiredValidationCheck components to adjust the logging level for invalid access tokens. By surfacing these incidents as errors rather than debug messages, the changes improved visibility and alerting for token-related issues, enabling faster detection and response. This targeted bug fix reduced log noise and ensured that security events are promptly noticed. The approach demonstrated attention to security best practices and effective use of Java for backend systems, with a focus on maintainability.