**Python:** Override __new__; return cached instance. Java: private constructor, static getInstance(), synchronized (or volatile+double-check) for thread-safety. **Trade-off:** Singleton = global state, hard to test. Prefer dependency injection....
This easy-level Python/Coding question appears frequently in data engineering interviews at companies like JP Morgan. While less common, it tests deeper understanding that distinguishes strong candidates. Mastering the underlying concepts (python) will help you answer variations of this question confidently.
Start by clearly defining the core concept being asked about. Interviewers want to see that you understand the fundamentals before diving into implementation details. Structure your answer with a definition, then explain the practical application with a concise example.
Python: Override __new__; return cached instance. Java: private constructor, static getInstance(), synchronized (or volatile+double-check) for thread-safety.
Trade-off: Singleton = global state, hard to test. Prefer dependency injection. Use for: connection pools, config loaders—single shared resource.
class Singleton:
_instance = None
def __new__(cls):
if cls._instance is None:
cls._instance = super().__new__(cls)
return cls._instance
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Analyze My Answer — FreeAccording to DataEngPrep.tech, this is one of the most frequently asked Python/Coding interview questions, reported at 1 company. DataEngPrep.tech maintains a curated database of 1,863+ real data engineering interview questions across 7 categories, verified by industry professionals.