[Solved] Examine the following class snippet:class ParkingFloor { List spots; void addSpot(Spot spot) { spots.add(spot); } }What is the primary issue with this class design? | LLD

LLD - Design — Parking Lot System

Examine the following class snippet:

class ParkingFloor {
  List spots;
  void addSpot(Spot spot) {
    spots.add(spot);
  }
}

What is the primary issue with this class design?

AThe method addSpot should return a boolean indicating success.

BThe 'spots' list is not initialized before adding elements.

CThe class should not have a method to add spots dynamically.

DThe Spot parameter should be of type Vehicle instead.

Step-by-Step Solution

Solution:

Step 1: Analyze the class definition
The class ParkingFloor has a List named spots but no constructor or initialization shown.
Step 2: Identify the problem
Without initializing 'spots' (e.g., new ArrayList<>()), calling spots.add(spot) will cause a NullPointerException.
Final Answer:
The 'spots' list is not initialized before adding elements. -> Option B
Quick Check:
Check if 'spots' is initialized before use [OK]

Quick Trick: Always initialize collections before use [OK]

Common Mistakes:

MISTAKES

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