LEGACY VS MODERN SECURITY HANDLING IN JAVA: A COMPARATIVE STUDY OF OPENSAML, SPRING SECURITY, AND JWT-BASED AUTHENTICATION

Enterprises must make important decisions about replacing outdated security features with more secure, scalable, and maintainable alternatives as they update their Java applications. Three popular Java security frameworks—OpenSAML, Spring Security OAuth2, and JWT-based authentication—are compared in this paper. Their architectural models, language integrations, and vulnerability exposure in Java 8 and Java 17 environments are evaluated. The study highlights compatibility, performance, and security risks that arise during version upgrades as it examines at significant shifts from XML-based security to annotation-driven and token-based security. We measure improvements in code maintainability, testability, and CVE reduction using benchmark testing, real-world deployment scenarios, and static analysis tools (e.g., OWASP Dependency-Check, SpotBugs). Our research shows that modern security stacks are much better in terms of performance, ease of integration, and long-term maintainability. However, they also need careful migration planning to avoid regressions. This study fills in a big gap in the literature by systematically comparing old and new security methods in Java across LTS versions. It also provides helpful guidance to developers and architects who plans secure Java Modernization.