Trace Java Static and Instance Field Initialization
Company: Pinduoduo
Role: Software Engineer
Category: Software Engineering Fundamentals
Difficulty: medium
Interview Round: Technical Screen
Overview: Consider a Java class with static fields `a` and `c`, an instance field `b`, and this initialization: `c = 2`; the constructor executes `a++`, `b++`, and `c++`. Make the API or object boundaries explicit, then cover invariants, edge cases, testing strategy, and operational trade-offs.