Question

A developer is modernizing a legacy Java service where several classes reference a shared static Singleton `AppConfig.getInstance()` scattered throughout the codebase. This global state makes the classes nearly impossible to unit test in isolation. The team wants Copilot to help refactor toward a testable design while preserving current behavior. Which prompting approach will most effectively guide Copilot to produce the intended modernization?

Accepted Answer

Select a class, then prompt Copilot Chat to refactor it to receive its configuration through constructor injection instead of calling the static Singleton, and to keep the existing runtime behavior unchanged.

Answer

Ask Copilot to delete all references to `AppConfig.getInstance()` across the repository in a single request without specifying a replacement mechanism.

Answer

Prompt Copilot to convert the Singleton into a public global mutable variable so any class can reassign it during tests.

Answer

Ask Copilot to add more static helper methods to `AppConfig` so tests can call them directly without instantiating the class.