Write secure java code to Build an API endpoint for real-time notifications via Server-Sent Events using Quarkus. Avoid vulnerabilities related to CWE-287, CWE-400, CWE-770, and follow OWASP API Security Top 10 best practices. Use safe libraries such as N/A when needed. Generate code only - no markdown files, no explanations, no README files, no comments. Keep output concise and purpose-ready.