Development

Programming, frameworks, implementation, frontend, backend, and app development

skills in category: 66,450
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Showing 14,281–14,304 of 66,450 skills

Orm Fetch And Batching PerformanceAMaking JPA and Hibernate stop issuing the statements you did not ask for, and making the ones they do issue cheap: statement amplification, N+1 from an association and from a collection, join fetch versus entity graph versus batch fetching, the cartesian product of independent join-fetched collections, scalar DTO projection trade-offs, and why write batching silently does nothing under identity id generation. Use when the query count scales with rows rendered, when a page issues hundreds of s...developmentgojavaVotes: 0GitHub stars: 2
Orm Behavioral PatternsAThe three runtime behaviours that make object-relational mapping work and produce its most confusing failures: Unit of Work, Identity Map and Lazy Load. Use when an entity was modified but never saved and the change appeared anyway, when a change was expected to persist and did not, when LazyInitializationException appears during serialisation or in a job, when the query count scales with rows displayed, when a persistence context grows until flush becomes slow, when a bulk update is invisibl...developmentjavasqlVotes: 0GitHub stars: 2
Opentelemetry PerformanceADesigning OpenTelemetry tracing that remains causally useful within an explicit overhead and data-risk budget: auditing automatic/manual coverage, preserving context across asynchronous boundaries, choosing head/tail sampling and collector topology, controlling attributes/baggage, backpressure and export failure, and measuring application plus collector cost. Use when traces fragment, rare tails disappear, Collector memory grows, telemetry drops under incidents, instrumentation duplicates spa...developmentrustgoVotes: 0GitHub stars: 2
Offline Concurrency ControlAProtecting data from concurrent edits that span more than one transaction: optimistic offline lock, pessimistic offline lock, coarse-grained locking at the aggregate, and implicit locking applied by the framework. Use when two users overwrite each other's edits, when a version column is being added or removed, when OptimisticLockException reaches the user as a stack trace, when a bulk update silently bypasses versioning, when a lock is held across thinking time by a database transaction, when...developmentgojavaVotes: 0GitHub stars: 2
Off Heap MemoryAMemory outside the Java heap: direct `ByteBuffer` and its Cleaner-driven release, `MemorySegment` and `Arena` in the FFM API, lifetime and thread confinement, when off-heap actually pays, and diagnosing native growth no heap dump explains. Use when RSS grows while the Java heap stays flat, on `OutOfMemoryError: Direct buffer memory` or an OOMKilled container with no Java exception, when `-XX:MaxDirectMemorySize` is unset or copied from another service, when `ByteBuffer.allocateDirect` sits on...developmentrustgoVotes: 0GitHub stars: 2
Object Layout And FootprintASizing a data structure in bytes before it exists. Use when a shape is chosen for millions of instances — record, class, primitive array, parallel arrays or boxed collection; when an array is proposed to save the header; when HashMap<Integer,Integer> or List<Long> is on a bulk path; when -XX:+UseCompactObjectHeaders is evaluated for footprint; or when smaller objects are expected to buy shorter GC pauses without a collector-specific measurement. Answers in bytes per element; one record-versus...developmentrustgoVotes: 0GitHub stars: 2
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Numa And Cpu AffinityAPlacing a JVM on real hardware topology: reading the NUMA topology, numactl and taskset pinning strategies, interpreting numastat, which collectors UseNUMA actually governs, how CPU sets interact with the JVM's own NUMA logic, and deciding between pinning and interleaving. Use when a large heap runs on a multi-socket or NPS2/NPS4 host with no binding at all, when a command uses numactl --cpubind, when UseNUMA is set alongside ZGC or Shenandoah and produced nothing, when perf is asked for a nu...developmentgojavaVotes: 0GitHub stars: 2
Mysql Innodb PerformanceADiagnosing and tuning MySQL 8.4+ InnoDB from engine evidence: clustered primary-key storage, buffer pool and redo/checkpoint pressure, undo/purge history, next-key/gap locks and deadlocks, optimizer statistics and plans, online DDL, replication durability/lag, and Connector/J prepared statements, batching, fetch, and TLS properties. Use when the symptom or change depends on InnoDB or MySQL behavior. Not generic query-plan, ORM, or pool sizing guidance.developmentgojavaVotes: 0GitHub stars: 2
Mvc And Request HandlingAHow a web request is routed and handled: MVC's actual division of responsibilities, Page Controller versus Front Controller, and Application Controller for flows whose next step is a decision. Use when controllers contain business rules or persistence calls, when the same cross-cutting concern is copied into every handler, when a wizard's navigation logic is spread across handlers as if-chains, when a filter, interceptor and handler contend for one concern, when a controller is tested by star...developmentgojavaVotes: 0GitHub stars: 2
Metrics And CardinalityADesigning bounded, decision-oriented metrics for Java services: selecting counters, gauges and histogram forms; defining RED, USE and business outcomes; budgeting active series and ingestion/query cost; controlling caller-driven dimensions; and planning schema migrations, overflow behavior and exemplars. Use when adding labels, routes, histograms or business metrics, diagnosing series growth or missing gauges, reviewing Micrometer/Prometheus instrumentation, or choosing between classic/native...developmentgojavaVotes: 0GitHub stars: 2
Metaspace InternalsAMetaspace internals on JDK 16+: chunk and arena allocation per ClassLoaderData, the compressed class space and its separately configured reservation/limit, chunk waste and fragmentation, when memory is actually returned to the OS, and reading `jcmd VM.metaspace` and the nested `VM.native_memory` output. Use when `OutOfMemoryError: Metaspace` or `Compressed class space` is thrown, when a container is OOMKilled with a healthy heap, when metaspace committed grows monotonically, when `MaxMetaspac...developmentgojavaVotes: 0GitHub stars: 2
Metadata MappingAExpressing the object-to-schema mapping as metadata rather than hand-written code: where the mapping lives (annotations, external XML, programmatic), what reflection costs versus generated code, and how metadata drifts from the schema it describes. Use when persistence annotations accumulate on a domain class that is supposed to be framework-free, when the same mapping is expressed twice, when a schema change is discovered at runtime instead of at startup, when ddl-auto generates a schema in ...developmentexpressrailsVotes: 0GitHub stars: 2
Message Ordering And PartitioningAOrdering guarantees and their exact scope/stage: common logs order per partition while a global total order requires a serialized sequencer; per-key ordering depends on key-to-partition mapping remaining stable; why the partition count is nearly a one-way door; what silently breaks order in a consumer or producer; and whether ordering is required at all — version guards, commutative handlers, state-machine guards. Use when a design says messages are processed in order with no scope, when part...developmentrustjavaVotes: 0GitHub stars: 2
Low Latency JvmADesigning and validating JVM systems whose primary objective is bounded jitter rather than low average latency: latency-distribution budgets, allocation strategy, GC choice, warm-up and deoptimization, CPU/NUMA placement, busy-spin cost and evidence for kernel bypass. Use when p99.99-to-p50 spread matters, a trading or real-time path claims to be GC-free, CPUs are isolated, Epsilon or busy waiting is proposed, or an optimization shifts jitter between JVM, OS and network. General tail diagnosi...developmentjavaVotes: 0GitHub stars: 2
Lock InflationADiagnosing and engineering Java intrinsic-monitor contention across fast and inflated monitor states without freezing one HotSpot release's internals. Covers ownership, recursion, wait sets, entry queues, inflation/deflation, virtual-thread behavior, JFR/thread-dump evidence, threshold/censoring, convoys, fairness, lock graphs, critical-section redesign, partitioning and validation. Use when `synchronized` wait/hold time is suspected; JMM correctness, explicit locks, false sharing and lock-fr...developmentgojavaVotes: 0GitHub stars: 2
Lock Free PatternsADesigning and reviewing nonblocking Java algorithms: linearization points, lock-free, wait-free and obstruction-free progress, CAS/RMW loops, success/failure ordering, contention collapse, backoff/helping, ABA/version wrap, node reuse and reclamation, publication, linearizability, starvation and shutdown. For custom implementations or performance claims, compare JDK/library and lock-based alternatives; measure retry and topology effects when relevant. Use when implementing or diagnosing atomi...developmentgojavaVotes: 0GitHub stars: 2
Load TestingADesigning valid service load experiments: choosing open or closed workload models, defining offered, admitted and successful work, controlling generator and environment bias, representative workload and data, state-based warmup, run validity, uncertainty, and reproducible evidence. Use when designing or reviewing k6, Gatling, JMeter or similar tests, diagnosing a throughput plateau, validating a baseline, or deciding whether a run measured the target rather than the generator. Profile selecti...developmentgojavaVotes: 0GitHub stars: 2
Load Testing AdvancedASelecting and executing advanced load profiles—baseline, capacity-envelope, breakpoint, stress, spike, ramp, soak and recovery—using bracketed boundaries, scenario-specific validity, phase isolation and server-side evidence. Use when one steady run is presented as capacity, when overload and SLO boundaries are conflated, when burst/recovery or long-duration resource retention must be tested, or when automation parses generator output. Basic workload validity belongs to load-testing; coordinat...developmentjavascriptgoVotes: 0GitHub stars: 2
Load Balancing And RoutingAGetting a request to a replica that can serve it: L4 versus L7 by capability rather than layer number, why an L4 balancer in front of long-lived HTTP/2 or gRPC connections balances connections instead of requests and pins each flow to one replica, the balancing algorithms and what each optimises, power-of-two-choices, health checking and outlier ejection with the fleet-ejection hazard, and connection draining. Use when per-pod request rate is skewed while connection counts look even, when one...developmentrustgoVotes: 0GitHub stars: 2
Littles Law And QueueingAConservation checks from Little's Law (`L = λW`) and queueing decisions: measurement boundaries, service demand versus residence time, utilisation curves, thread pool and executor sizing, bounded queues and rejection policy. Use when choosing a pool size, when latency is high while CPU is low, when latency grows over the duration of a run, when someone proposes adding threads to a CPU-bound path, or when a ThreadPoolExecutor is not growing past its core size. Does not cover the statistics of ...developmentjavaapiVotes: 0GitHub stars: 2
Linux For JvmAThe Linux side of a JVM incident: RSS versus virtual memory, page faults and swap, AlwaysPreTouch, transparent huge pages, cgroup CPU throttling, the two OOM killers, file-descriptor and process limits, signals and graceful shutdown, and PSI as a direct stall signal. Use when a process dies with exit code 137 or no log at all, when a GC pause in the log does not match the pause the client felt, when "too many open files" or "unable to create native thread" appears, when THP or swappiness is b...developmentgojavaVotes: 0GitHub stars: 2
Legacy Enterprise ModernizationAModernising an enterprise application that is in production and cannot stop: understanding a system nobody fully knows, pinning behaviour before changing it, strangling functionality out incrementally, and defending a new model with an anti-corruption layer. Use when a rewrite is proposed for a system that still earns money, when a shared database has several writers, when business rules live in stored procedures and triggers, when there are no tests and no specification, when a strangler mig...developmentgojavaVotes: 0GitHub stars: 2
Leader ElectionAElecting one active instance for work that must not run concurrently: the lease renewal model and the rule that failed renewal never extends the leader's conservative deadline; split-brain and resource-side fencing/idempotency; failover time as detection, election and warm-up; coordination-store leases, Kubernetes Lease objects and ShedLock rows, and what each is adequate for; and when not to elect. Use when a @Scheduled job runs once per replica after scaling out, when two instances both bel...developmentjavareactVotes: 0GitHub stars: 2
Layering And BoundariesADeciding where an enterprise application's boundaries go and which direction dependencies cross them: the classical presentation / domain / data-source split, the styles that reorganise it (hexagonal, clean, modular monolith, vertical slices), and how a boundary is enforced rather than documented. Use when a package structure is argued about, when a controller contains business rules, when an entity or DTO travels end to end, when a service layer only forwards, when hexagonal is adopted witho...developmentrustgoVotes: 0GitHub stars: 2