ERYI

Java Servlets evolved as an efficient, standardized way to handle web requests in Java, replacing earlier CGI solutions and serving as the foundation for Spring MVC's architecture through the DispatcherServlet.

A quick refresher on how cookies keep state, why servers maintain sessions, and where stateless tokens such as JWT fit in.

Document the root cause of repeated passphrase prompts when Obsidian's Git plugin pushes via SSH, recap how the SSH handshake works, and configure ssh-agent so keys are unlocked automatically.

Walk through several singleton implementations to explain why synchronized, double-checked locking and volatile matter, and how eager, static-inner-class and enum singletons compare.