Your question is Singleton Pattern Explained. Take a moment with it on the right.
Talk me through your thinking if you like. When you're confident, submit your answer and I'll grade it like a real screen (7/10 or better passes).
Explain how the Singleton pattern works, and can you implement it in Java.
Describe how the implementation prevents external construction and how it behaves when multiple threads access it concurrently. Discuss one appropriate implementation choice, such as an enum, initialization-on-demand holder, or double-checked locking, and mention important limitations. Scope your answer to standard Java and the JVM, without requiring a runnable application.
