Drills

When should Angular state use a signal, computed value, or effect?

Separates source state, derived state, and synchronization with external systems to prevent reactive loops.

When should behavior or state be static rather than instance-based in Java?

Connects static ownership to constants and stateless operations while exposing the risks of global mutable state and initialization.

Concept questionMedium~7 min

When should you not build an AI agent?

Rejects agent complexity when rules, APIs, search, ordinary automation, or a bounded model call solve the task more safely.

Artificial IntelligenceGenerative AILarge Language Models

Artificial IntelligenceLarge Language Models

When should you not use an LLM?

Identifies tasks better served by deterministic code, search, rules, or conventional models because of correctness, latency, cost, or control.

Architecture scenarioMedium~7 min

When should you override a Spring bean with a mock in a test?

Overrides unstable external boundaries intentionally while keeping the framework behavior and real collaborators the test claims to prove.

JavaSpring Boot

When should you use a type annotation, a type assertion, or satisfies?

Separates declared variable types, unchecked developer assertions, and compatibility checking that preserves useful inferred types.

JavaScriptTypeScript

When should you use Instant, LocalDateTime, or ZonedDateTime in Java?

Chooses Java time types by business meaning and handles time zones, daylight-saving transitions, persistence, and testable clocks.

Artificial IntelligenceGenerative AILarge Language Models

When should you use structured output versus tool calling?

Distinguishes a typed final answer from a model request for the application to execute an external capability.

When would you choose a comprehension or a generator expression in Python?

Compares eager collections with lazy one-pass generation through memory, timing, reuse, readability, and resource ownership.

Python

When would you choose an interface or an abstract class in Java?

Compares Java interfaces and abstract classes through contract, shared state, implementation reuse, and evolution trade-offs.

When would you choose ArrayList or LinkedList in Java?

Compares Java list implementations using actual access patterns, traversal cost, memory locality, and insertion location.

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.

Concept questionMedium~7 min

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