Extension functions are statically dispatched based on the compile‑time type, not the runtime type. They don’t actually override member functions. A common pitfall is calling an extension on a variable typed as a base class and expecting the derived extension to run.
Advanced answer
Deep dive
Expanding on the short answer — what usually matters in practice:
Context (tags): kotlin, extension, dispatch, oop
JVM: memory (heap/stack), GC, and what drives latency.
Contracts: equals/hashCode/toString, mutability and consequences.
Explain the "why", not just the "what" (intuition + consequences).
Trade-offs: what you gain/lose (time, memory, complexity, risk).
Edge cases: empty inputs, large inputs, invalid inputs, concurrency.
Examples
A tiny example (an explanation template):
// Example: discuss trade-offs for "extension-functions:-how-are-they-dispatched-and"
function explain() {
// Start from the core idea:
// Extension functions are statically dispatched based on the compile‑time type, not the runt
}
Common pitfalls
Too generic: no concrete trade-offs or examples.
Mixing average-case and worst-case (e.g., complexity).