`inline` copies the function body to the call site. It can reduce overhead of higher-order functions by avoiding lambda allocations and virtual calls (but increases bytecode size).
Advanced answer
Deep dive
Expanding on the short answer — what usually matters in practice:
Context (tags): inline, performance, lambdas
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 "what-does-`inline`-do-and-when-can-it-help-perfo"
function explain() {
// Start from the core idea:
// `inline` copies the function body to the call site. It can reduce overhead of higher-order
}
Common pitfalls
Too generic: no concrete trade-offs or examples.
Mixing average-case and worst-case (e.g., complexity).