Drills

When would you choose ReentrantLock instead of synchronized?

Chooses an explicit lock only when timed, interruptible, conditional, or advanced acquisition behavior justifies manual lifecycle.

Architecture scenarioMedium~7 min

When would you use an Angular route resolver?

Chooses between blocking navigation for essential data and rendering a page-owned loading state.

When would you use a Next.js layout instead of a template?

Connects layouts and templates to navigation, state lifetime, Effects, and deliberate remounting in the App Router.

Next.jsReactTypeScript

When would you use Angular signals instead of RxJS Observables?

Chooses between synchronous UI state and asynchronous event streams without treating either model as a replacement for the other.

Artificial IntelligenceGenerative AILarge Language Models

When would you use a smaller model instead of the most capable one?

Uses task bounds and evaluation evidence to choose smaller models for lower latency, cost, capacity, privacy, or local execution.

When would you use HashMap, LinkedHashMap, or TreeMap?

Chooses among common Java map implementations by lookup behavior, iteration order, sorting, range operations, and key contracts.

When would you use input, output, or model signals in Angular?

Distinguishes one-way data, events, and deliberate two-way component contracts without hiding ownership.

When would you use minimal APIs in ASP.NET Core?

Explains minimal APIs, endpoint groups, dependency injection, typed results, filters, and when they fit real services.

.NETASP.NET CoreC#

When would you use Promise.all, allSettled, race, or any?

Chooses promise combinators by success criteria, failure semantics, cancellation needs, and the fate of losing operations.

JavaScript

When would you use Spring application events instead of durable messaging?

Separates in-process decoupling from durable cross-process delivery and makes timing, failure, and transaction expectations explicit.

JavaSpring Boot

When would you use `useLayoutEffect` instead of `useEffect`?

Chooses post-paint synchronization by default and reserves layout effects for pre-paint measurement or correction.

ReactTypeScript

Artificial IntelligenceGenerative AILarge Language Models

When would you use zero-shot versus few-shot prompting?

Uses examples to clarify ambiguous task behavior while accounting for token cost, bias, maintenance, and evaluation evidence.

Which memory metrics would you monitor for a .NET service?

Identifies useful memory and GC signals for alerting without overwhelming the team with noisy telemetry.

.NETASP.NET CoreC#

Why are Java arrays covariant while generics are invariant?

Contrasts runtime-checked array covariance with compile-time-safe generic invariance and explains why generic arrays are restricted.

Why are raw types and unchecked warnings risky in Java?

Treats raw types as a legacy compatibility boundary that can introduce heap pollution and delayed runtime failures.

Why are side effects risky in Java stream operations?

Explains interference, stateful lambdas, execution-order assumptions, safe collection, and visibility of unavoidable effects.

Debugging scenarioMedium~7 min

Why can large allocations hurt a .NET application?

Covers the Large Object Heap, big buffers, fragmentation pressure, and practical ways to avoid loading too much at once.

.NETC#

Why can mutable default arguments cause bugs in Python?

Diagnoses shared mutable function defaults and explains safe initialization without turning the behavior into a superstition.

Python

Artificial IntelligenceLarge Language Models

Why can the same prompt produce different answers?

Connects probabilistic decoding and changing service conditions to output variation, reproducibility limits, and appropriate testing.

Debugging scenarioMedium~7 min

Why does ConcurrentModificationException happen, and how do you modify a collection safely?

Explains fail-fast iteration, safe removal patterns, structural modification, and why the exception is not a concurrency guarantee.

Debugging scenarioMedium~7 min

Why does middleware ordering matter in ASP.NET Core?

Explains how middleware order affects authentication, authorization, error handling, routing, CORS, and response behavior.

.NETASP.NET CoreC#

Why does React Strict Mode repeat renders and Effects in development?

Uses development-only repeated rendering, Effects, and ref callbacks to expose impurity and missing cleanup.

ReactTypeScript

Why does tracking matter in Angular template control flow?

Connects modern template blocks and stable list identity to DOM reuse, component state, and rendering correctness.

Why is an Angular route guard not an authorization boundary?

Uses guards for navigation UX while keeping permissions and data enforcement on the trusted server.