Background: I am working in a Java environment using Spring Boot, where I often encounter scenarios where global variable state management is critical, especially within singleton services. I have been exploring the idea of using annotations to automate cleanup global variable after used.

Goal: My objective is to streamline global variable management using annotations, enhancing code clarity and maintaining thread safety across singleton services.

Proposed Solution: I propose creating a custom annotation, let's call it @CleanAfterUse, that leverages ThreadLocal under-the-hood. This annotation would handle initialization, management, and cleanup of thread-local state automatically, reducing boilerplate code and potential errors.


What are the best practices for implementing annotations in Java to manage ThreadLocal variables effectively? Are there alternative approaches within the Java ecosystem that could achieve similar thread-local state management goals?

  • I'm not sure, in your scenario, how you know when to cleanup a global resource. Are you planning to create and destroy these resources on every use?
    – JimmyJames
    Commented Jul 5 at 18:54
  • @JimmyJames I'm just worried that this would encourage the casual use of globals. The biggest argument against them isn't technical. It's what they do to us humans. Commented Jul 5 at 19:12
  • @candied_orange I'm just trying to understand. If these are single-use resources, I'm not sure what point there is in making them global.
    – JimmyJames
    Commented Jul 5 at 19:19
  • 1
    Can you edit your question to clarify something that might be ambiguous? Java doesn't have the concept of a literal global variable, at least not like some other languages where you declare an identifier as global. Global can mean an object passed around by dependency injection from object to object, where "global" is more of a concept that a language feature. Commented Jul 5 at 19:30
  • 1
    @MuhammadHaris Please edit your question to say what you actually mean, at the moment it's very confusing for a reader when you refer to "global variables" when you don't actually mean global variables. Commented Jul 6 at 16:06


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