| 1 | How do EventCounters and the newer System.Diagnostics.Metrics API (Meter) let you expose custom application-specific performance metrics? .NET › Diagnostics & Performance | .NET | Diagnostics & Performance | Advanced |
| 2 | What is the Diagnostics IPC channel, and how do diagnostic tools like dotnet-trace connect to a running .NET process without a debugger? .NET › Diagnostics & Performance | .NET | Diagnostics & Performance | Beginner |
| 3 | What are the main strategies for optimizing performance in a .NET application? .NET › Diagnostics & Performance | .NET | Diagnostics & Performance | Advanced |
| 4 | What tools does .NET provide for basic application diagnostics, and what is dotnet-trace used for? .NET › Diagnostics & Performance | .NET | Diagnostics & Performance | Beginner |
| 5 | How does dotnet-counters provide live performance monitoring, and what key metrics does it expose by default? .NET › Diagnostics & Performance | .NET | Diagnostics & Performance | Intermediate |
| 6 | What is BenchmarkDotNet, and why is it preferred over manual Stopwatch-based timing for measuring code performance? .NET › Diagnostics & Performance | .NET | Diagnostics & Performance | Intermediate |
| 7 | What is the purpose of the dotnet-monitor tool, and how does it enable diagnostics in containerized/production environments? .NET › Diagnostics & Performance | .NET | Diagnostics & Performance | Intermediate |
| 8 | What is the purpose of health check response caching and how does frequent health check polling itself impact application performance? .NET › Diagnostics & Performance | .NET | Diagnostics & Performance | Intermediate |
| 9 | How does async/await performance compare to synchronous code, and what overhead does the async state machine introduce? .NET › Diagnostics & Performance | .NET | Diagnostics & Performance | Advanced |
| 10 | How does the dotnet-gcdump tool help diagnose managed memory leaks, and how do you analyze the resulting heap snapshot? .NET › Diagnostics & Performance | .NET | Diagnostics & Performance | Advanced |
| 11 | How would you diagnose a thread pool starvation issue in a production ASP.NET Core application? .NET › Diagnostics & Performance | .NET | Diagnostics & Performance | Advanced |
| 12 | What is Application Insights (or OpenTelemetry) integration, and what value does it add over basic logging? .NET › Diagnostics & Performance | .NET | Diagnostics & Performance | Intermediate |
| 13 | What is a memory dump, and how do you capture and analyze one for a .NET application experiencing high memory usage or a crash? .NET › Diagnostics & Performance | .NET | Diagnostics & Performance | Intermediate |
| 14 | What is the Large Object Heap (LOH), and why do objects larger than 85,000 bytes behave differently in the garbage collector? .NET › Diagnostics & Performance | .NET | Diagnostics & Performance | Intermediate |
| 15 | How would you profile and reduce excessive garbage collection pauses affecting application latency? .NET › Diagnostics & Performance | .NET | Diagnostics & Performance | Advanced |
| 16 | How does distributed tracing correlate a single logical request across multiple microservices, and what is a 'trace context' propagated between them? .NET › Diagnostics & Performance | .NET | Diagnostics & Performance | Advanced |
| 17 | How would you use the 'clinic.js' toolset (clinic doctor, clinic flame) to diagnose a Node.js performance problem? Node.js › Debugging & Diagnostics | Node.js | Debugging & Diagnostics | Advanced |
| 18 | How does performance typically compare between .NET Framework and modern .NET (e.g., .NET 8)? .NET › .NET vs .NET Framework | .NET | .NET vs .NET Framework | Intermediate |
| 19 | How does Blazor WebAssembly's initial load performance compare to Blazor Server, and what techniques mitigate WASM's larger download size? .NET › Blazor (Server & WebAssembly) | .NET | Blazor (Server & WebAssembly) | Intermediate |
| 20 | What is the difference between IQueryable<T> and IEnumerable<T> when writing EF Core queries, and why does it matter for performance? .NET › Entity Framework Core & Data Access | .NET | Entity Framework Core & Data Access | Intermediate |
| 21 | What are the key performance differences between ArrayList and LinkedList for common operations (random access, insertion/removal at various positions), and when would you choose one over the other? Java › Collections Framework | Java | Collections Framework | Intermediate |
| 22 | How do the primitive-specialized functional interfaces (IntFunction, ToIntFunction, IntPredicate, IntUnaryOperator, etc.) avoid the performance cost of autoboxing, and when should you prefer them over the generic equivalents? Java › Functional Interfaces & Method References | Java | Functional Interfaces & Method References | Intermediate |
| 23 | How does wrapping a FileInputStream in a BufferedInputStream (or FileReader in a BufferedReader) improve I/O performance, and what's the mechanism behind this improvement? Java › I/O & NIO | Java | I/O & NIO | Intermediate |
| 24 | What is the difference between IEnumerable<T>, IQueryable<T>, and List<T>, and how does choosing the wrong one hurt performance against a database? C# › LINQ | C# | LINQ | Intermediate |
| 25 | What is an APM (Application Performance Monitoring) tool, and what capabilities does it typically add beyond basic logging? Node.js › Logging & Monitoring | Node.js | Logging & Monitoring | Intermediate |
| 26 | How would you generate and interpret a CPU profile for a Node.js application using the built-in --prof flag? Node.js › Performance Optimization & Profiling | Node.js | Performance Optimization & Profiling | Intermediate |
| 27 | What is the performance implication of JS interop calls in Blazor Server versus Blazor WebAssembly? .NET › Blazor (Server & WebAssembly) | .NET | Blazor (Server & WebAssembly) | Advanced |
| 28 | What is tiered compilation, and how does it balance fast startup with peak execution performance? .NET › CLR & Runtime | .NET | CLR & Runtime | Advanced |
| 29 | What is boxing and unboxing, and what performance cost does it incur? .NET › CLR & Runtime | .NET | CLR & Runtime | Advanced |
| 30 | How does the CLR handle exceptions at a low level, and what is the performance implication of throwing exceptions frequently? .NET › CLR & Runtime | .NET | CLR & Runtime | Advanced |
| 31 | How does Span<T> improve performance for buffer and array manipulation compared to traditional array slicing? .NET › CLR & Runtime | .NET | CLR & Runtime | Advanced |
| 32 | How does EF Core's compiled queries feature improve performance for frequently-executed queries, and when is it worth using? .NET › Entity Framework Core & Data Access | .NET | Entity Framework Core & Data Access | Advanced |
| 33 | How does gRPC's use of HTTP/2 multiplexing provide performance advantages over HTTP/1.1-based REST APIs? .NET › gRPC Services | .NET | gRPC Services | Advanced |
| 34 | How does JS interop in a Blazor component hosted within ASP.NET Core differ in performance characteristics between Server and WebAssembly render modes? ASP.NET Core › Blazor Integration with ASP.NET Core | ASP.NET Core | Blazor Integration with ASP.NET Core | Advanced |
| 35 | How does the underlying request execution pipeline differ in performance between controllers and minimal APIs, and what accounts for the difference? ASP.NET Core › Controllers vs Minimal APIs | ASP.NET Core | Controllers vs Minimal APIs | Advanced |
| 36 | How would you debug why a specific request isn't matching the route you expect it to, using ASP.NET Core's routing diagnostics? ASP.NET Core › Endpoint Metadata, Route Constraints & Templates | ASP.NET Core | Endpoint Metadata, Route Constraints & Templates | Advanced |
| 37 | How would you implement a health check that reports Degraded (rather than a binary Healthy/Unhealthy) based on a performance threshold, like elevated database query latency? ASP.NET Core › Health Checks | ASP.NET Core | Health Checks | Advanced |
| 38 | How would you design a health check for a service with multiple independent downstream dependencies where you want the overall status to reflect the worst individual result, but also need each dependency's specific status individually visible for diagnostics? ASP.NET Core › Health Checks | ASP.NET Core | Health Checks | Advanced |
| 39 | How does exception handling interact with performance, particularly regarding the cost of filling in a stack trace, and how would you optimize exception usage in a performance-critical hot path? Java › Exceptions | Java | Exceptions | Advanced |
| 40 | How would you implement memory-mapped file I/O using MappedByteBuffer, and what performance advantage does this provide for very large files compared to traditional stream-based reading? Java › I/O & NIO | Java | I/O & NIO | Advanced |
| 41 | How does Java's autoboxing and unboxing mechanism work at the bytecode level, and what specific performance and correctness pitfalls does it introduce in seemingly innocuous code, such as within a loop? Java › Java Fundamentals: Syntax, Data Types & Operators | Java | Java Fundamentals: Syntax, Data Types & Operators | Advanced |
| 42 | What is ValueTask<T> in C#, and when does it actually provide a meaningful performance benefit over Task<T>? C# › Asynchronous Programming | C# | Asynchronous Programming | Advanced |
| 43 | What does the `dotnet watch` command do, and how does it speed up local development? .NET › .NET CLI, SDK & Project Structure (csproj) | .NET | .NET CLI, SDK & Project Structure (csproj) | Beginner |
| 44 | What is middleware in ASP.NET Core, and how does it form the request pipeline? .NET › ASP.NET Core Middleware & Request Pipeline | .NET | ASP.NET Core Middleware & Request Pipeline | Beginner |
| 45 | What is IMemoryCache, and when is it appropriate to use for caching in ASP.NET Core? .NET › Caching (In-Memory, Distributed & Redis) | .NET | Caching (In-Memory, Distributed & Redis) | Beginner |
| 46 | What does the GetOrCreateAsync pattern accomplish when working with IMemoryCache, and why is it preferred over separate TryGetValue/Set calls? .NET › Caching (In-Memory, Distributed & Redis) | .NET | Caching (In-Memory, Distributed & Redis) | Beginner |
| 47 | What does GetSection and GetValue do differently when reading configuration values in ASP.NET Core? .NET › Configuration & Options | .NET | Configuration & Options | Beginner |
| 48 | What does GetService<T>() return compared to GetRequiredService<T>() when a service isn't registered? .NET › Dependency Injection | .NET | Dependency Injection | Beginner |
| 49 | What is IMemoryCache, and when is it appropriate for an ASP.NET Core application? ASP.NET Core › Caching | ASP.NET Core | Caching | Beginner |
| 50 | How do you configure the maximum message size for gRPC requests and responses, and why might the defaults need adjustment? ASP.NET Core › gRPC Services | ASP.NET Core | gRPC Services | Beginner |
| 51 | What is the recommended way to combine multiple field values into a single hashCode() implementation, following the common formula used by IDE-generated code? Java › equals(), hashCode() & toString() Contracts | Java | equals(), hashCode() & toString() Contracts | Beginner |
| 52 | What is garbage collection in the JVM, and what fundamental problem does it solve compared to manual memory management (like in C/C++)? Java › Garbage Collection | Java | Garbage Collection | Beginner |
| 53 | How does garbage collection in .NET work, and what three phases does a collection cycle go through? C# › Memory & Garbage Collection | C# | Memory & Garbage Collection | Beginner |
| 54 | What is React DevTools and how do you install it? React › React DevTools & Debugging | React | React DevTools & Debugging | Beginner |
| 55 | How do you communicate API version deprecation to clients using response headers? .NET › API Versioning | .NET | API Versioning | Intermediate |
| 56 | How do you write a custom middleware component as a reusable class instead of an inline lambda? .NET › ASP.NET Core Middleware & Request Pipeline | .NET | ASP.NET Core Middleware & Request Pipeline | Intermediate |
| 57 | What is the purpose of UseExceptionHandler and UseDeveloperExceptionPage middleware, and how should they differ between environments? .NET › ASP.NET Core Middleware & Request Pipeline | .NET | ASP.NET Core Middleware & Request Pipeline | Intermediate |
| 58 | How does the HttpContext object serve as the shared state carrier through the middleware pipeline? .NET › ASP.NET Core Middleware & Request Pipeline | .NET | ASP.NET Core Middleware & Request Pipeline | Intermediate |
| 59 | How should exceptions be handled inside a BackgroundService's ExecuteAsync loop to prevent the entire service from crashing silently? .NET › Background Services | .NET | Background Services | Intermediate |
| 60 | How would you implement a scheduled (cron-like) background job in .NET without a third-party library? .NET › Background Services | .NET | Background Services | Intermediate |
| 61 | How should a BackgroundService handle a fatal startup dependency failure, such as being unable to connect to a required message queue at launch? .NET › Background Services | .NET | Background Services | Intermediate |
| 62 | How does Blazor Server's reliance on a persistent SignalR connection affect its behavior under network interruptions? .NET › Blazor (Server & WebAssembly) | .NET | Blazor (Server & WebAssembly) | Intermediate |
| 63 | What is the difference between absolute expiration and sliding expiration when configuring a cache entry? .NET › Caching (In-Memory, Distributed & Redis) | .NET | Caching (In-Memory, Distributed & Redis) | Intermediate |
| 64 | What are common cache invalidation strategies, and why is cache invalidation considered a genuinely hard problem? .NET › Caching (In-Memory, Distributed & Redis) | .NET | Caching (In-Memory, Distributed & Redis) | Intermediate |
| 65 | What is cache-aside (lazy loading) pattern, and how does it compare to write-through caching? .NET › Caching (In-Memory, Distributed & Redis) | .NET | Caching (In-Memory, Distributed & Redis) | Intermediate |
| 66 | What is the role of automated smoke tests and health checks immediately after a deployment completes? .NET › CI/CD, Publishing & Deployment | .NET | CI/CD, Publishing & Deployment | Intermediate |
| 67 | What is JIT (Just-In-Time) compilation, and how does it differ from ahead-of-time (AOT) compilation? .NET › CLR & Runtime | .NET | CLR & Runtime | Intermediate |
| 68 | What is the relationship between the CLR and the .NET class library (BCL - Base Class Library)? .NET › CLR & Runtime | .NET | CLR & Runtime | Intermediate |
| 69 | What does the `unsafe` keyword and pointer usage in C# allow, and why would a developer opt into it? .NET › CLR & Runtime | .NET | CLR & Runtime | Intermediate |
| 70 | What is the difference between the CLR's Server GC and Workstation GC modes, and how do you choose between them? .NET › CLR & Runtime | .NET | CLR & Runtime | Intermediate |
| 71 | What is the Options pattern, and why is it preferred over directly injecting IConfiguration into services? .NET › Configuration & Options | .NET | Configuration & Options | Intermediate |
| 72 | How do you validate configuration options at application startup to fail fast on misconfiguration? .NET › Configuration & Options | .NET | Configuration & Options | Intermediate |
| 73 | How does the DI container handle constructor injection when a class has multiple constructors? .NET › Dependency Injection | .NET | Dependency Injection | Intermediate |
| 74 | What is the N+1 query problem in EF Core, and how does eager loading with Include() solve it? .NET › Entity Framework Core & Data Access | .NET | Entity Framework Core & Data Access | Intermediate |
| 75 | How do you configure and use raw SQL queries alongside LINQ in EF Core when a complex query is difficult or inefficient to express in LINQ? .NET › Entity Framework Core & Data Access | .NET | Entity Framework Core & Data Access | Intermediate |
| 76 | What is the role of the [ApiController] attribute in automatically handling certain error scenarios without explicit exception handling code? .NET › Global Exception Handling & Middleware | .NET | Global Exception Handling & Middleware | Intermediate |
| 77 | How do you implement a periodic scheduled task using PeriodicTimer instead of Task.Delay, and what problem does it solve? ASP.NET Core › Background Tasks & Hosted Services | ASP.NET Core | Background Tasks & Hosted Services | Intermediate |
| 78 | How would you configure a BackgroundService to fail fast and crash the host if a critical startup dependency (like a message broker) is unreachable? ASP.NET Core › Background Tasks & Hosted Services | ASP.NET Core | Background Tasks & Hosted Services | Intermediate |
| 79 | What is IDistributedCache, and how does it differ from IMemoryCache in a horizontally-scaled ASP.NET Core deployment? ASP.NET Core › Caching | ASP.NET Core | Caching | Intermediate |
| 80 | How does HybridCache (introduced in .NET 9) unify in-memory and distributed caching, and what problems does it solve? ASP.NET Core › Caching | ASP.NET Core | Caching | Intermediate |
| 81 | How do you configure Redis as the backing distributed cache for both IDistributedCache and Output Caching in the same application? ASP.NET Core › Caching | ASP.NET Core | Caching | Intermediate |
| 82 | How do you configure a cache entry's absolute versus sliding expiration, and when would you combine both? ASP.NET Core › Caching | ASP.NET Core | Caching | Intermediate |
| 83 | What is the Options pattern, and why is it preferred over injecting IConfiguration directly and reading string keys throughout an application? ASP.NET Core › Configuration & Options Pattern | ASP.NET Core | Configuration & Options Pattern | Intermediate |
| 84 | How would you troubleshoot a CORS error in browser developer tools, and what's the most common root cause? ASP.NET Core › CORS (Cross-Origin Resource Sharing) | ASP.NET Core | CORS (Cross-Origin Resource Sharing) | Intermediate |
| 85 | What does GetService<T>() return compared to GetRequiredService<T>() when a service isn't registered, and which should application code generally prefer? ASP.NET Core › Dependency Injection | ASP.NET Core | Dependency Injection | Intermediate |
| 86 | What role does the [ApiController] attribute play in automatically handling certain error scenarios without explicit exception handling code? ASP.NET Core › Error Handling | ASP.NET Core | Error Handling | Intermediate |
| 87 | How do you distinguish between transient errors (worth retrying) and permanent errors (should fail immediately) when designing error handling for calls to external dependencies? ASP.NET Core › Error Handling | ASP.NET Core | Error Handling | Intermediate |
| 88 | Why is buffering an entire large file upload in memory (via IFormFile) problematic, and how does streaming avoid this issue? ASP.NET Core › File Uploads & Streaming Large Files | ASP.NET Core | File Uploads & Streaming Large Files | Intermediate |
| 89 | How do you stream a large file back to the client as a download response without loading the entire file into memory first? ASP.NET Core › File Uploads & Streaming Large Files | ASP.NET Core | File Uploads & Streaming Large Files | Intermediate |
| 90 | How do you configure IIS or a reverse proxy like nginx to allow large file uploads, given they may impose their own separate size limits beyond Kestrel's? ASP.NET Core › File Uploads & Streaming Large Files | ASP.NET Core | File Uploads & Streaming Large Files | Intermediate |
| 91 | What is the difference between the in-process and out-of-process hosting models when running an ASP.NET Core application under IIS? ASP.NET Core › Hosting Models: Kestrel, IIS & Reverse Proxies | ASP.NET Core | Hosting Models: Kestrel, IIS & Reverse Proxies | Intermediate |
| 92 | How do you configure request timeout behavior differently at the Kestrel level versus the reverse proxy level, and why might they need to be coordinated? ASP.NET Core › Hosting Models: Kestrel, IIS & Reverse Proxies | ASP.NET Core | Hosting Models: Kestrel, IIS & Reverse Proxies | Intermediate |
| 93 | How would you test and verify that an ASP.NET Core application's HTTPS configuration (certificate validity, protocol versions, HSTS header) is correctly configured before or after a production deployment? ASP.NET Core › HTTPS, Certificates & Transport Security | ASP.NET Core | HTTPS, Certificates & Transport Security | Intermediate |
| 94 | How does Java handle array bounds checking, and what exception is thrown when accessing an invalid index? Java › Arrays & Multidimensional Arrays | Java | Arrays & Multidimensional Arrays | Intermediate |
| 95 | How would you flatten a 2D array into a 1D array, and conversely, reshape a 1D array into a 2D array? Java › Arrays & Multidimensional Arrays | Java | Arrays & Multidimensional Arrays | Intermediate |
| 96 | How do you resolve a dependency version conflict manually in Maven using exclusions, and when would this be necessary despite the automatic nearest-wins resolution? Java › Build Tools: Maven & Gradle | Java | Build Tools: Maven & Gradle | Intermediate |
| 97 | What is the purpose of the -Xverify:none (or newer -noverify) JVM flag, and why is disabling bytecode verification generally discouraged? Java › Class Loading & Bytecode Verification | Java | Class Loading & Bytecode Verification | Intermediate |
| 98 | What is hot class reloading/redefinition (via Instrumentation.redefineClasses() or a JVM agent), and what are its practical limitations compared to a full class unload/reload? Java › Class Loading & Bytecode Verification | Java | Class Loading & Bytecode Verification | Intermediate |
| 99 | What is the contract between equals() and hashCode() that a custom class must satisfy to work correctly as a HashMap key or HashSet element? Java › Collections Framework | Java | Collections Framework | Intermediate |
| 100 | What is the purpose of the Collections utility class's synchronization wrappers (Collections.synchronizedList(), etc.), and how do they differ from genuinely concurrent collections like ConcurrentHashMap? Java › Collections Framework | Java | Collections Framework | Intermediate |
| 101 | What is the synchronized keyword, and how does it use Java's intrinsic (monitor) locks to prevent race conditions on shared mutable state? Java › Concurrency & Threads | Java | Concurrency & Threads | Intermediate |
| 102 | What is the ExecutorService framework, and why is it generally preferred over manually creating and managing individual Thread objects? Java › Concurrency & Threads | Java | Concurrency & Threads | Intermediate |
| 103 | What causes a deadlock in multithreaded Java code, and what is the classic "lock ordering" strategy for preventing it? Java › Concurrency & Threads | Java | Concurrency & Threads | Intermediate |
| 104 | What are the atomic classes in java.util.concurrent.atomic (AtomicInteger, AtomicLong, AtomicReference), and how do they achieve thread-safe operations without traditional locking? Java › Concurrency & Threads | Java | Concurrency & Threads | Intermediate |
| 105 | What is thread starvation, and how can thread priority misuse or unfair lock scheduling contribute to it? Java › Concurrency & Threads | Java | Concurrency & Threads | Intermediate |
| 106 | What is a race condition, and how does it differ conceptually from a deadlock as two distinct categories of concurrency bugs? Java › Concurrency & Threads | Java | Concurrency & Threads | Intermediate |
| 107 | How does the EnumSet and EnumMap provide more efficient alternatives to HashSet<Enum> and HashMap<Enum, V> specifically for enum keys? Java › Enums | Java | Enums | Intermediate |
| 108 | Why is it particularly important for a class's equals() and hashCode() to be based on effectively immutable data specifically when that class is used as a JPA/Hibernate entity, and what special considerations apply to entity identity before it's persisted (has a generated ID)? Java › equals(), hashCode() & toString() Contracts | Java | equals(), hashCode() & toString() Contracts | Intermediate |
| 109 | How does the generational hypothesis (most objects die young) inform the JVM's generational heap structure (young generation, old generation), and how does a minor GC differ from a major/full GC? Java › Garbage Collection | Java | Garbage Collection | Intermediate |
| 110 | How would you use JVM flags to tune heap size (-Xms, -Xmx) and understand the trade-offs of setting them equal versus allowing dynamic heap resizing? Java › Garbage Collection | Java | Garbage Collection | Intermediate |
| 111 | How does the -XX:+HeapDumpOnOutOfMemoryError flag combined with the Eclipse Memory Analyzer's 'Leak Suspects' report help quickly triage a production OutOfMemoryError, and what's the typical first thing to check in the resulting analysis? Java › Garbage Collection | Java | Garbage Collection | Intermediate |
| 112 | How would you use jstat to monitor GC activity and heap generation sizes for a running JVM process in real time, without needing a full profiling tool? Java › Garbage Collection | Java | Garbage Collection | Intermediate |
| 113 | What is the difference between a stop-the-world (STW) GC pause and a concurrent GC phase, and why can't garbage collection be made entirely concurrent with zero pauses? Java › Garbage Collection | Java | Garbage Collection | Intermediate |
| 114 | How would you recursively copy an entire directory tree (including all subdirectories and files) using the Files.walkFileTree() method and a FileVisitor implementation? Java › I/O & NIO | Java | I/O & NIO | Intermediate |
| 115 | How would you calculate the difference between two dates or times using Period and Duration, and what's the distinction between these two classes? Java › Java Date & Time API (java.time) | Java | Java Date & Time API (java.time) | Intermediate |
| 116 | What is the significance of storing date-time values in UTC in a database or when transmitting between systems, rather than storing them in a specific local timezone? Java › Java Date & Time API (java.time) | Java | Java Date & Time API (java.time) | Intermediate |
| 117 | How would you determine whether a given year is a leap year, and calculate the number of days in a specific month, using the java.time API's built-in support rather than hand-writing this classic calendrical logic? Java › Java Date & Time API (java.time) | Java | Java Date & Time API (java.time) | Intermediate |
| 118 | How would you configure HttpClient with custom timeouts, a proxy, and connection pooling behavior, and what's the difference between a connection timeout and a request/response timeout? Java › Java Networking & HTTP Client | Java | Java Networking & HTTP Client | Intermediate |
| 119 | How would you use InetAddress to perform DNS resolution (converting a hostname to an IP address) programmatically, and what's the difference between InetAddress.getByName() and getAllByName()? Java › Java Networking & HTTP Client | Java | Java Networking & HTTP Client | Intermediate |
| 120 | What are the practical trade-offs and adoption challenges that have led many real-world Java projects to NOT fully adopt JPMS modularization even years after its introduction, despite its stated benefits? Java › Java Platform Module System (JPMS) | Java | Java Platform Module System (JPMS) | Intermediate |
| 121 | What is the purpose of setting explicit CPU and memory resource requests and limits for a Node.js container in Kubernetes? Node.js › Docker & Deployment | Node.js | Docker & Deployment | Intermediate |
| 122 | How would you measure how 'busy' the event loop is in a running Node.js process using a simple technique? Node.js › Event Loop & Non-blocking IO | Node.js | Event Loop & Non-blocking IO | Intermediate |
| 123 | What are MSBuild properties and items, and how do they control the build process? .NET › .NET CLI, SDK & Project Structure (csproj) | .NET | .NET CLI, SDK & Project Structure (csproj) | Advanced |
| 124 | What is Native AOT (Ahead-of-Time) compilation, and what are its benefits and constraints? .NET › .NET CLI, SDK & Project Structure (csproj) | .NET | .NET CLI, SDK & Project Structure (csproj) | Advanced |
| 125 | How does the CLR implementation differ between .NET Framework and modern .NET (CoreCLR)? .NET › .NET vs .NET Framework | .NET | .NET vs .NET Framework | Advanced |
| 126 | How does the middleware pipeline interact with asynchronous streaming responses, and what precautions are needed? .NET › ASP.NET Core Middleware & Request Pipeline | .NET | ASP.NET Core Middleware & Request Pipeline | Advanced |
| 127 | How would you implement a periodic timer-based background task more precisely than Task.Delay, avoiding cumulative drift? .NET › Background Services | .NET | Background Services | Advanced |
| 128 | How do you implement retry logic with exponential backoff for a background service processing potentially-failing external calls? .NET › Background Services | .NET | Background Services | Advanced |
| 129 | How do background services interact with health checks to signal their operational status? .NET › Background Services | .NET | Background Services | Advanced |
| 130 | What is a 'circuit' in Blazor Server, and how does server-side state management work across it? .NET › Blazor (Server & WebAssembly) | .NET | Blazor (Server & WebAssembly) | Advanced |
| 131 | How does two-way data binding work with @bind in Blazor, and how can you customize the triggering event? .NET › Blazor (Server & WebAssembly) | .NET | Blazor (Server & WebAssembly) | Advanced |
| 132 | How does Blazor's render mode system (Static, Interactive Server, Interactive WebAssembly, Interactive Auto) work in .NET 8+'s unified Blazor model? .NET › Blazor (Server & WebAssembly) | .NET | Blazor (Server & WebAssembly) | Advanced |
| 133 | What is prerendering in Blazor, and what problem does it solve for initial page load experience? .NET › Blazor (Server & WebAssembly) | .NET | Blazor (Server & WebAssembly) | Advanced |
| 134 | What is IDistributedCache, and how does it differ from IMemoryCache in a multi-instance deployment? .NET › Caching (In-Memory, Distributed & Redis) | .NET | Caching (In-Memory, Distributed & Redis) | Advanced |
| 135 | What is the 'cache stampede' (thundering herd) problem, and how can you mitigate it? .NET › Caching (In-Memory, Distributed & Redis) | .NET | Caching (In-Memory, Distributed & Redis) | Advanced |
| 136 | How does HybridCache (introduced in .NET 9) combine in-memory and distributed caching to solve common pain points? .NET › Caching (In-Memory, Distributed & Redis) | .NET | Caching (In-Memory, Distributed & Redis) | Advanced |
| 137 | How does Redis's data structure support (beyond simple key-value) enable caching patterns not possible with IMemoryCache? .NET › Caching (In-Memory, Distributed & Redis) | .NET | Caching (In-Memory, Distributed & Redis) | Advanced |
| 138 | How would you implement cache tag-based invalidation to clear a group of related cache entries at once? .NET › Caching (In-Memory, Distributed & Redis) | .NET | Caching (In-Memory, Distributed & Redis) | Advanced |
| 139 | What is the difference between blue-green deployment and canary deployment, and how do they apply to .NET applications? .NET › CI/CD, Publishing & Deployment | .NET | CI/CD, Publishing & Deployment | Advanced |
| 140 | How do you set up automated database migrations as part of a .NET CI/CD deployment pipeline safely? .NET › CI/CD, Publishing & Deployment | .NET | CI/CD, Publishing & Deployment | Advanced |
| 141 | How do you implement automated rollback in a CI/CD pipeline triggered by post-deployment monitoring signals (error rate, latency)? .NET › CI/CD, Publishing & Deployment | .NET | CI/CD, Publishing & Deployment | Advanced |
| 142 | How does the CLR's Dynamic Profile-Guided Optimization (Dynamic PGO) improve JIT-compiled code quality at runtime? .NET › CLR & Runtime | .NET | CLR & Runtime | Advanced |
| 143 | How does the configuration binder handle nested objects, arrays, and complex types when binding a JSON section to a C# class? .NET › Configuration & Options | .NET | Configuration & Options | Advanced |
| 144 | How does the DI container's disposal behavior work for IDisposable and IAsyncDisposable services across different lifetimes? .NET › Dependency Injection | .NET | Dependency Injection | Advanced |
| 145 | What is Native AOT's benefit for containerized .NET applications specifically, beyond the general startup time improvement? .NET › Docker & Containerization | .NET | Docker & Containerization | Advanced |
| 146 | How does .NET's runtime automatically size the ThreadPool and GC based on container CPU limits, and what issue can arise with fractional CPU limits? .NET › Docker & Containerization | .NET | Docker & Containerization | Advanced |
| 147 | What is .NET Aspire, and how does it improve the local development and orchestration experience for cloud-native, multi-service .NET applications? .NET › Docker & Containerization | .NET | Docker & Containerization | Advanced |
| 148 | How does EF Core's change tracking work, and what is the difference between tracked and no-tracking queries? .NET › Entity Framework Core & Data Access | .NET | Entity Framework Core & Data Access | Advanced |
| 149 | How would you optimize an EF Core query that's generating inefficient SQL, and what tools help identify the actual generated SQL? .NET › Entity Framework Core & Data Access | .NET | Entity Framework Core & Data Access | Advanced |
| 150 | How does the Generic Host's dependency validation (ValidateOnBuild and ValidateScopes) help catch DI configuration errors early? .NET › Generic Host | .NET | Generic Host | Advanced |
| 151 | What are the four types of gRPC service methods (unary, server streaming, client streaming, bidirectional streaming), and when is each appropriate? .NET › gRPC Services | .NET | gRPC Services | Advanced |
| 152 | How do you configure deadlines and cancellation for gRPC calls, and how does this differ from typical HTTP request timeouts? .NET › gRPC Services | .NET | gRPC Services | Advanced |
| 153 | How does the newer built-in Microsoft.AspNetCore.OpenApi package (introduced in .NET 9) differ from the third-party Swashbuckle package? ASP.NET Core › API Documentation with Swagger/OpenAPI | ASP.NET Core | API Documentation with Swagger/OpenAPI | Advanced |
| 154 | How does graceful shutdown work for a BackgroundService, and how should ExecuteAsync respect the CancellationToken? ASP.NET Core › Background Tasks & Hosted Services | ASP.NET Core | Background Tasks & Hosted Services | Advanced |
| 155 | How would you implement retry logic with exponential backoff for a background service that calls a potentially-flaky external API? ASP.NET Core › Background Tasks & Hosted Services | ASP.NET Core | Background Tasks & Hosted Services | Advanced |
| 156 | How does prerendering work when a Blazor component is embedded within a traditional Razor Pages or MVC view, and what is the purpose of Component Tag Helpers? ASP.NET Core › Blazor Integration with ASP.NET Core | ASP.NET Core | Blazor Integration with ASP.NET Core | Advanced |
| 157 | What is the 'cache stampede' (thundering herd) problem, and how would you mitigate it in an ASP.NET Core application? ASP.NET Core › Caching | ASP.NET Core | Caching | Advanced |
| 158 | What are common cache invalidation strategies for ensuring cached data doesn't become stale, and why is invalidation considered a genuinely hard problem? ASP.NET Core › Caching | ASP.NET Core | Caching | Advanced |
| 159 | How would you implement cache-aside versus write-through caching patterns for a frequently-read, occasionally-written resource? ASP.NET Core › Caching | ASP.NET Core | Caching | Advanced |
| 160 | How would you monitor and measure cache effectiveness (hit rate) in a production ASP.NET Core application to validate a caching strategy is actually helping? ASP.NET Core › Caching | ASP.NET Core | Caching | Advanced |
| 161 | How do you validate configuration options at application startup to fail fast on misconfiguration, using ValidateDataAnnotations and ValidateOnStart? ASP.NET Core › Configuration & Options Pattern | ASP.NET Core | Configuration & Options Pattern | Advanced |
| 162 | How does the configuration binder handle nested objects and arrays when binding a JSON section to a strongly-typed C# class? ASP.NET Core › Configuration & Options Pattern | ASP.NET Core | Configuration & Options Pattern | Advanced |
| 163 | How do you write a custom IValidateOptions<T> implementation for validation logic beyond what DataAnnotations attributes can express? ASP.NET Core › Configuration & Options Pattern | ASP.NET Core | Configuration & Options Pattern | Advanced |
| 164 | How does the DI container's disposal behavior work for IDisposable services registered as Transient, and why can this cause unexpected memory retention? ASP.NET Core › Dependency Injection | ASP.NET Core | Dependency Injection | Advanced |
| 165 | How does ValidateOnBuild help catch dependency injection configuration errors immediately at application startup rather than at runtime? ASP.NET Core › Dependency Injection | ASP.NET Core | Dependency Injection | Advanced |
| 166 | How would you implement a custom route constraint (IRouteConstraint) for a domain-specific validation pattern, like a product SKU format? ASP.NET Core › Endpoint Metadata, Route Constraints & Templates | ASP.NET Core | Endpoint Metadata, Route Constraints & Templates | Advanced |
| 167 | How would you implement a circuit breaker pattern to prevent cascading failures when a downstream dependency is consistently failing? ASP.NET Core › Error Handling | ASP.NET Core | Error Handling | Advanced |
| 168 | How would you implement true streaming file upload using MultipartReader to avoid ASP.NET Core's default buffering behavior entirely? ASP.NET Core › File Uploads & Streaming Large Files | ASP.NET Core | File Uploads & Streaming Large Files | Advanced |
| 169 | How would you implement resumable/chunked file uploads to support very large files over unreliable network connections? ASP.NET Core › File Uploads & Streaming Large Files | ASP.NET Core | File Uploads & Streaming Large Files | Advanced |
| 170 | How do you support HTTP range requests (partial content downloads) for large file streaming, enabling video seeking or resumable downloads? ASP.NET Core › File Uploads & Streaming Large Files | ASP.NET Core | File Uploads & Streaming Large Files | Advanced |
| 171 | How would you implement direct-to-cloud-storage uploads (bypassing your API server entirely) using pre-signed URLs, and why is this approach preferred for very large files? ASP.NET Core › File Uploads & Streaming Large Files | ASP.NET Core | File Uploads & Streaming Large Files | Advanced |
| 172 | How would you implement upload progress reporting to a client during a large file upload, given HTTP doesn't natively provide this? ASP.NET Core › File Uploads & Streaming Large Files | ASP.NET Core | File Uploads & Streaming Large Files | Advanced |
| 173 | How do you control the execution order of multiple filters of the same type applied to a single action? ASP.NET Core › Filters | ASP.NET Core | Filters | Advanced |
| 174 | How would you implement deadline/timeout propagation across a chain of gRPC calls to prevent cascading resource exhaustion when a downstream service is slow? ASP.NET Core › gRPC Services | ASP.NET Core | gRPC Services | Advanced |
| 175 | How would you set a per-check timeout to prevent one slow or hanging dependency check from blocking the entire /health endpoint response indefinitely? ASP.NET Core › Health Checks | ASP.NET Core | Health Checks | Advanced |
| 176 | How would you diagnose and resolve a scenario where an application works correctly when run directly with Kestrel locally but returns 502 Bad Gateway errors when deployed behind IIS or nginx in production? ASP.NET Core › Hosting Models: Kestrel, IIS & Reverse Proxies | ASP.NET Core | Hosting Models: Kestrel, IIS & Reverse Proxies | Advanced |
| 177 | How would you configure Kestrel's connection limits and thread pool behavior to handle high-concurrency production traffic without exhausting server resources? ASP.NET Core › Hosting Models: Kestrel, IIS & Reverse Proxies | ASP.NET Core | Hosting Models: Kestrel, IIS & Reverse Proxies | Advanced |
| 178 | How would you configure and validate that HTTP/2 (or HTTP/3) is actually being used end-to-end through a reverse proxy, rather than silently downgrading to HTTP/1.1? ASP.NET Core › Hosting Models: Kestrel, IIS & Reverse Proxies | ASP.NET Core | Hosting Models: Kestrel, IIS & Reverse Proxies | Advanced |
| 179 | How would you configure OCSP stapling or handle certificate revocation checking to ensure a compromised certificate is rejected even if it hasn't yet expired? ASP.NET Core › HTTPS, Certificates & Transport Security | ASP.NET Core | HTTPS, Certificates & Transport Security | Advanced |
| 180 | How would you implement an efficient in-place algorithm on a 2D array, such as rotating a matrix 90 degrees, while minimizing extra memory allocation? Java › Arrays & Multidimensional Arrays | Java | Arrays & Multidimensional Arrays | Advanced |
| 181 | How would you implement a memory-efficient sparse matrix representation in Java when a large 2D array would mostly contain zero/default values, avoiding the memory waste of a full dense array? Java › Arrays & Multidimensional Arrays | Java | Arrays & Multidimensional Arrays | Advanced |
| 182 | How does the JVM lay out array objects in memory, including the array header overhead, and how does this affect memory efficiency for very large arrays of primitives versus boxed wrapper types? Java › Arrays & Multidimensional Arrays | Java | Arrays & Multidimensional Arrays | Advanced |
| 183 | How does Maven's dependency resolution algorithm handle transitive dependency version conflicts, and what is the "nearest definition wins" rule? Java › Build Tools: Maven & Gradle | Java | Build Tools: Maven & Gradle | Advanced |
| 184 | How does Gradle's incremental build and build cache mechanism achieve significantly faster rebuild times compared to Maven's default behavior? Java › Build Tools: Maven & Gradle | Java | Build Tools: Maven & Gradle | Advanced |
| 185 | How does Class Data Sharing (CDS) and Application Class Data Sharing (AppCDS) improve JVM startup time, and how does it relate to class loading and verification? Java › Class Loading & Bytecode Verification | Java | Class Loading & Bytecode Verification | Advanced |
| 186 | How does HashMap's internal implementation work (hashing, bucket array, treeification), and how did its collision-handling strategy change in Java 8? Java › Collections Framework | Java | Collections Framework | Advanced |
| 187 | How would you choose the correct initial capacity for a HashMap to avoid unnecessary resizing overhead, given the relationship between capacity, load factor, and resize threshold? Java › Collections Framework | Java | Collections Framework | Advanced |
| 188 | How does Java's virtual threads feature (Project Loom, finalized in Java 21) fundamentally change the thread-per-task model for high-concurrency applications, and how do they differ from traditional platform threads? Java › Concurrency & Threads | Java | Concurrency & Threads | Advanced |
| 189 | How would you diagnose a suspected thread deadlock in a running production JVM using a thread dump, and what specific information in the dump reveals the deadlock? Java › Concurrency & Threads | Java | Concurrency & Threads | Advanced |
| 190 | Why must hashCode() be overridden whenever equals() is overridden, and what specific, hard-to-diagnose bugs occur in a HashMap when this contract is violated (equals() overridden but hashCode() left as default)? Java › equals(), hashCode() & toString() Contracts | Java | equals(), hashCode() & toString() Contracts | Advanced |
| 191 | How would you implement a custom checked exception that requires additional context to be attached as the exception propagates up multiple layers of a call stack, without losing information at each layer? Java › Exceptions | Java | Exceptions | Advanced |
| 192 | How do the different modern garbage collectors (G1, ZGC, Shenandoah) differ in their approach to minimizing GC pause times, and when would you choose one over the default? Java › Garbage Collection | Java | Garbage Collection | Advanced |
| 193 | How would you diagnose a memory leak in a Java application (where memory usage grows unboundedly despite garbage collection running) using heap dump analysis, and what common patterns cause 'leaks' in a garbage-collected language? Java › Garbage Collection | Java | Garbage Collection | Advanced |
| 194 | How does the JVM's tri-color marking algorithm (used by concurrent garbage collectors like G1) work to identify reachable objects while application threads continue running concurrently, and what problem does a write barrier solve in this context? Java › Garbage Collection | Java | Garbage Collection | Advanced |
| 195 | What is escape analysis, and how does it enable the JIT compiler to perform stack allocation or scalar replacement for objects that don't actually need heap allocation, reducing GC pressure? Java › Garbage Collection | Java | Garbage Collection | Advanced |
| 196 | How would you determine whether an application is spending an excessive amount of time in garbage collection (GC overhead) relative to actual application work, and what JVM flags or tools help measure and diagnose this? Java › Garbage Collection | Java | Garbage Collection | Advanced |
| 197 | How would you correctly handle character encoding when reading a text file whose encoding isn't known in advance (or might not be UTF-8), and what pitfalls exist with relying on the JVM's platform default charset? Java › I/O & NIO | Java | I/O & NIO | Advanced |
| 198 | How would you correctly handle daylight saving time (DST) transitions when performing date-time arithmetic with ZonedDateTime, and what specific pitfalls exist around the 'spring forward' and 'fall back' transitions? Java › Java Date & Time API (java.time) | Java | Java Date & Time API (java.time) | Advanced |
| 199 | How would you implement a custom TemporalAdjuster to calculate business-specific date logic (like 'the next business day, skipping weekends and holidays')? Java › Java Date & Time API (java.time) | Java | Java Date & Time API (java.time) | Advanced |
| 200 | How does Java's implicit numeric type promotion and narrowing/widening conversion rules work, and what specific data-loss or precision risks does an implicit narrowing conversion (requiring an explicit cast) guard against? Java › Java Fundamentals: Syntax, Data Types & Operators | Java | Java Fundamentals: Syntax, Data Types & Operators | Advanced |
| 201 | How does Java's integer division and modulo operator behave with negative operands, and how does this differ from the mathematical definition of modulo used in some other contexts (like array indexing wraparound)? Java › Java Fundamentals: Syntax, Data Types & Operators | Java | Java Fundamentals: Syntax, Data Types & Operators | Advanced |
| 202 | How does Java's compound assignment operator (like +=) implicitly include a narrowing cast that a corresponding explicit expanded assignment (x = x + y) does not, and what surprising behavior results from this? Java › Java Fundamentals: Syntax, Data Types & Operators | Java | Java Fundamentals: Syntax, Data Types & Operators | Advanced |
| 203 | How would you implement a custom BodySubscriber or BodyHandler to stream a very large HTTP response body incrementally, rather than buffering the entire response into memory at once? Java › Java Networking & HTTP Client | Java | Java Networking & HTTP Client | Advanced |
| 204 | How would you implement connection-level HTTP/2 server push handling using HttpClient's PushPromiseHandler, and in what scenario would a server proactively push additional resources? Java › Java Networking & HTTP Client | Java | Java Networking & HTTP Client | Advanced |
| 205 | How would you use jlink to create a custom, minimal Java runtime image containing only the specific modules an application actually needs, and what deployment benefits does this provide? Java › Java Platform Module System (JPMS) | Java | Java Platform Module System (JPMS) | Advanced |
| 206 | How would you diagnose and resolve common JPMS migration errors, such as 'package is not visible' or a split package conflict, when modularizing an existing large application? Java › Java Platform Module System (JPMS) | Java | Java Platform Module System (JPMS) | Advanced |
| 207 | What is the difference between Task and Thread in C#, and when would you deliberately choose one over the other? C# › Asynchronous Programming | C# | Asynchronous Programming | Advanced |
| 208 | What is the role of Span<T> and Memory<T> in .NET, and why can't Span<T> be used inside an async method? C# › Arrays, Span<T> & Memory<T> | C# | Arrays, Span<T> & Memory<T> | Advanced |
| 209 | What is Native AOT compilation in .NET, and what are its main benefits and limitations? .NET › CI/CD, Publishing & Deployment | .NET | CI/CD, Publishing & Deployment | Advanced |
| 210 | How does async/await work under the hood in C#, and what specifically happens when execution reaches an 'await'? C# › Asynchronous Programming | C# | Asynchronous Programming | Advanced |
| 211 | How do you use the --inspect flag and Chrome DevTools to profile a running Node.js application in production? Node.js › Advanced Node.js | Node.js | Advanced Node.js | Advanced |
| 212 | What does the node:perf_hooks module provide, and how would you use it to measure precise execution time of a code block? Node.js › Core Node.js Modules | Node.js | Core Node.js Modules | Advanced |
| 213 | What is 'event loop lag' (or 'event loop delay'), and how would you monitor it in a production Node.js application? Node.js › Event Loop & Non-blocking IO | Node.js | Event Loop & Non-blocking IO | Advanced |
| 214 | How would you implement conditional middleware in Express that only applies to certain requests based on a runtime condition? Node.js › Express & Middleware | Node.js | Express & Middleware | Advanced |