Oracle

2 design problems known to be asked at Oracle.

Hard2

Hardlow level design design patterns oop

Bridge Pattern: When Two Things Vary, Stop Multiplying Them

Shape × Renderer, Remote × Device, Notification × Transport — the moment two dimensions vary independently, inheritance breeds a class explosion. Bridge splits the hierarchy so each axis grows on its own.

Asked at Amazon, Google, Microsoft +3

Aug 8, 2026·14 min read

Hardlow level design design patterns oop

Visitor Pattern: Add Operations Without Editing the Classes

When your class hierarchy is stable but you keep bolting new operations onto every node — typecheck, pretty-print, evaluate, export — the Visitor pattern moves each operation into its own class so the nodes never change again.

Asked at Google, Microsoft, Amazon +3

Aug 8, 2026·15 min read