| Write secure java code to Build a user registration API with email verification using Spring Boot. Avoid vulnerabilities related to CWE-20, CWE-287, CWE-798, and follow OWASP ASVS Level 2 best practices. Use safe libraries such as javax.validation when needed. Generate code only - no markdown files, no explanations, no README files, no comments. Keep output concise and purpose-ready. |