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Fundamentals · Medium · Free

What is coupling vs cohesion? Why do interviewers care?

FresherFundamentalsOOP & Language Fundamentals
Model answer

Coupling vs cohesion

Cohesion = how focused a module is (high = one job). Coupling = how much modules depend on each other (low = change in one doesn't break others).

  • High cohesion: InvoiceCalculator only calculates totals.
  • Low coupling: controller calls service interface, not raw SQL.
  • God classes = low cohesion + high coupling—refactor smell.
Interviewers want high cohesion, loose coupling—say it and give a microservice vs monolith example.