Securing Legacy Java Systems with Spring Security

Course Overview

This course is tailored for Java developers maintaining or modernizing legacy applications built with Jakarta EE 8 and Spring 5. As enterprise applications evolve, so do the threats they face. Spring Security offers a robust, customizable, and production-proven framework for implementing both fundamental and advanced security features with minimal overhead.

Through practical examples and real-world scenarios, you’ll gain hands-on expertise in securing web applications, REST APIs, and critical business services. Whether you’re integrating with OAuth 2.0 providers, implementing JWT-based stateless sessions, or managing user roles and permissions, this course equips you with the knowledge needed to safeguard your applications.

No prior Spring Security experience is required—this course builds a strong foundation and gradually transitions to advanced integration strategies suitable for real enterprise environments.

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You Will Learn To:

✅ Understand the core architecture and filter chain of Spring Security

✅ Implement authentication mechanisms like form login, basic auth, and token-based login

✅ Apply authorization rules with roles, permissions, and expression-based access control

✅ Secure REST endpoints with OAuth 2.0 and JSON Web Tokens (JWT)

✅ Integrate Spring Security seamlessly with existing Jakarta EE 8 components

✅ Evaluate alternative security frameworks (e.g., Apache Shiro, Keycloak) and understand why Spring Security often stands out

✅ Protect legacy systems while preparing for migration to Spring Boot or modern stacks

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Who Should Take This Course:

• Java developers working with legacy Jakarta EE or Spring MVC applications
• Teams responsible for updating authentication and authorization logic
• Architects and engineers planning a migration from monolithic apps to secure microservices
• Developers integrating with third-party identity providers using OAuth 2.0

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Technologies Covered:

• Spring 5 Framework – Foundational enterprise Java development framework
• Jakarta EE 8 – Key APIs in legacy enterprise systems, including Servlets, JAX-RS, and JSP
• OpenJDK 11 – Long-term support Java version widely used in production
• Spring Security – Main focus of the course
• OAuth 2.0 & JWT – Secure, stateless authentication strategies for modern APIs

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Core Security Concepts

✅ Authentication: Verifying User Identity Spring Security authenticates users by validating submitted credentials (e.g., username/password, token) against a configured identity store (database, LDAP, external providers). You’ll learn to plug in custom authentication providers and work with the AuthenticationManager.

✅ Authorization: Granting or Denying Access Authorization rules define what authenticated users can do. You’ll implement role-based and attribute-based access control using annotations (@PreAuthorize, @Secured) and expression-based rules.

✅ Security Filters: The Filter Chain That Processes Requests Spring Security processes HTTP requests through a powerful filter chain. You’ll explore how filters like UsernamePasswordAuthenticationFilter, BasicAuthenticationFilter, and ExceptionTranslationFilter work together to secure endpoints.

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Project Setup Checklist

1️⃣ Add Spring Security Dependencies

• Use spring-boot-starter-security or manually include Spring Security artifacts for legacy projects.
• Watch for transitive dependencies that might conflict with older Jakarta EE libraries.

2️⃣ Configure SecurityFilterChain (Java Config)

• Replace deprecated XML and WebSecurityConfigurerAdapter with @Bean public SecurityFilterChain.
• Configure HTTP security rules, form login, and custom filters inside this method.

3️⃣ Disable Deprecated WebSecurityConfigurerAdapter

• Spring Security 5.7+ treats this class as legacy. You’ll learn how to migrate to a modern, functional-style configuration.

4️⃣ Set Up Basic Authentication for Initial Testing

• Start simple: hardcode an in-memory user for rapid feedback.
• Validate your setup by protecting a test controller and accessing it with credentials.

5️⃣ Pro Tip: Use Spring Initializr to Bootstrap Your Project

• Visit start.spring.io to scaffold your project with the right dependencies, project structure, and Java version.
• Select “Spring Web” and “Spring Security” for a minimal secure web stack.