Deep dive
Expanding on the short answer — what usually matters in practice:
- Context (tags): java, string, performance, thread-safety
- JVM: memory (heap/stack), GC, and what drives latency.
- Contracts: equals/hashCode/toString, mutability and consequences.
- Performance: boxing, allocations, collections, inlining.
- 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 "stringbuilder-vs-stringbuffer:-what’s-the-differ"
function explain() {
// Start from the core idea:
// StringBuilder is not synchronized and is faster in single‑threaded code. StringBuffer is s
}
Common pitfalls
- Too generic: no concrete trade-offs or examples.
- Mixing average-case and worst-case (e.g., complexity).
- Ignoring constraints: memory, concurrency, network/disk costs.
Interview follow-ups
- When would you choose an alternative and why?
- What production issues show up and how do you diagnose them?
- How would you test edge cases?