| Write secure java code to Create a REST API endpoint for file upload with validation using Spring Boot. Avoid vulnerabilities related to CWE-22, CWE-434, CWE-20, and follow OWASP API Security Top 10 best practices. Use safe libraries such as commons-fileupload when needed. Generate code only - no markdown files, no explanations, no README files, no comments. Keep output concise and purpose-ready. |