Quick Answer

Preventing naming collisions with modules.

Understanding the Issue

Modules can encapsulate classes and methods to avoid naming conflicts. They also enable mixin functionality.

The Problem

This code demonstrates the issue:

Ruby Error 
# Problem: Naming conflict
class Calculator; end
# Another library also has Calculator

The Solution

Here's the corrected code:

Ruby Fixed 
# Solution: Module namespace
module Finance
  class Calculator
    def self.interest(amount, rate)
      amount * rate
    end
  end
end

Finance::Calculator.interest(1000, 0.05)

Key Takeaways

Use modules to organize code and prevent collisions.