Programming Languages & Core Development Topics
Programming languages, development fundamentals, coding concepts, and core data structures. Includes syntax, algorithms, memory management at a programming level, asynchronous patterns, and concurrency primitives. Also covers core data manipulation concepts like hashing, collections, error handling, and DOM manipulation for web development. Excludes tool-specific proficiency (see 'Tools, Frameworks & Implementation Proficiency').
Asynchronous and Event-Driven Programming
Non-blocking execution models: callbacks, promises and futures, async/await, event loops, and event-driven and reactive architectures. Covers reasoning about ordering, back-pressure, and error propagation in asynchronous flows, including data-fetching patterns. Central to modern frontend, backend, and mobile runtimes.
Functional Programming
Functional-style programming: pure functions, immutability, higher-order functions, closures, currying and partial application, and memoization, along with functional reactive patterns. Covers reasoning about code as composed transformations rather than mutable state, whether in a dedicated functional language or a multi-paradigm one. Increasingly probed for frontend and data-heavy work.
Language-Level Concurrency and Multithreading
Per-language and per-runtime concurrency: the threading and async APIs each language and platform provides (goroutines, channels, worker pools and pipelines in Go, threads, executors, ThreadPoolExecutor tuning and CompletableFuture in Java, Kotlin coroutines, dispatchers, Flow and structured concurrency, Swift GCD with queues and QoS, DispatchGroup, OperationQueue, actors and async/await, Android Handler/Looper, HandlerThread and thread pools, Flutter isolates, C++ std::thread and atomics, Python threads versus multiprocessing versus asyncio tasks, gather and graceful shutdown), each language's memory model and visibility guarantees (Java happens-before and volatile, C++11 memory orders such as relaxed, acquire and release, Objective-C and Swift atomic versus nonatomic), mobile main-thread rules and JNI thread attachment, cancellation and shutdown idioms, and the idioms for coordinating shared state safely in that language, including thread-safe caches, singletons and bounded queues. Also covers reproducing, testing and diagnosing races and deadlocks in a specific language or app, and migrating callback, GCD or thread-pool code to structured concurrency. Covers choosing and using a language's concurrency primitives correctly. Boundary: general synchronization theory, deadlock and lock-free algorithm internals, OS scheduling, database isolation levels, and callback or event-loop architecture are covered elsewhere.
Java Programming
The Java language and platform: type system, collections framework, generics, exceptions, the memory and JVM model, and idiomatic object-oriented Java. Covers writing correct Java and reasoning about its runtime and language semantics. A staple server-side and test-automation language surface.
Programming Fundamentals
Language-agnostic building blocks of writing code: variables, primitive and composite data types, scope and lifetime, functions and callbacks, control flow, and expressions versus statements. Covers the mental model a candidate needs before any language-specific or algorithmic depth. The baseline literacy layer of a technical screen.
Error Handling and Defensive Programming
Making code robust against bad input and failure: exceptions versus error returns, input validation, guard clauses, graceful degradation, and designing for the unhappy path. Covers where to handle versus propagate errors and how to fail safely without hiding bugs. A recurring probe of production maturity.
JavaScript and TypeScript Fundamentals
The JavaScript and TypeScript language surface: scope, closures, the this binding, prototypes and inheritance, the type system, modern ES features, and common language patterns. Covers the deep language-mechanics questions frontend and full-stack interviews lean on, independent of any framework. TypeScript's static typing is treated as an extension of the same core.
iOS Development (Swift and Objective-C)
Native iOS programming: the Swift language and Objective-C, Automatic Reference Counting and memory semantics, threading and concurrency on Apple platforms, and iOS SDK fundamentals. Covers writing correct native iOS code and reasoning about the platform's runtime and language rules. The primary Apple-platform mobile surface.
Android Development (Kotlin and Java)
Native Android programming: the Kotlin language and Java interoperability, coroutines and concurrency, Android collections and data structures, and platform fundamentals. Covers writing correct native Android code and reasoning about the Kotlin/JVM runtime on-device. The primary Android-platform mobile surface.