Development

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

skills in category: 66,450
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Showing 14,449–14,472 of 66,450 skills

DeoptimizationADeoptimisation and recompilation on HotSpot: uncommon traps and their reason codes, the none / maybe_recompile / reinterpret / make_not_entrant / make_not_compilable actions, jdk.Deoptimization in JFR, -XX:+TraceDeoptimization, the per-method trap limits and recompilation cutoffs, and diagnosing a method that never stabilises. Use when a method repeatedly shows "made not entrant" in the compilation log, when latency spikes correlate with class loading or a deploy, when a burst of "marked for ...developmentgojavaVotes: 0GitHub stars: 2
Delivery SemanticsAPrecise end-to-end delivery and processing semantics: acknowledgement placement, loss and duplicate windows, Kafka transactions, visibility leases, ambiguous outcomes and external side effects. Use when reviewing "exactly once", consumer commits, publisher confirms, redelivery or a handler that writes outside its broker. Idempotent handler design belongs to idempotency; retries, ordering, poison messages and fault assumptions have their own skills.developmentgojavaVotes: 0GitHub stars: 2
DebuggingAFinding the cause of a fault instead of a change that makes the symptom go away: reproducing before diagnosing, shrinking the reproduction until nothing is removable, stating a hypothesis that predicts an observation, changing one variable at a time, bisecting, and choosing which evidence to collect from a running production system before it is destroyed. Use when a fix is being guessed at, when a change "seems to work", when the same bug keeps coming back, when a fault cannot be reproduced, ...developmentgojavaVotes: 0GitHub stars: 2
Database PerformanceAEvidence-first triage and routing for database performance questions across SQL Server, MySQL/InnoDB, PostgreSQL, JDBC pools, ORM behavior, index portfolios, and bulk loading. Use when the symptom spans layers, the owning mechanism is unclear, or a database choice or migration needs structured comparison. This is a router; it does not replace the specialist skills that own a confirmed engine or mechanism.developmentgojavaVotes: 0GitHub stars: 2
Database Index DesignADesigning and governing an index portfolio across SQL Server, MySQL/InnoDB, and PostgreSQL: deriving composite keys from a workload, equality/range/order trade-offs, covering and partial indexes, write amplification, redundant-index consolidation, engine-specific semantics, and safe production creation or removal. Use when changing schema indexes for several queries or reviewing a table's index set. Not the diagnosis of one slow statement, which belongs to sql-query-performance.developmentgojavaVotes: 0GitHub stars: 2
Database Engine Selection And MigrationAChoosing among SQL Server, MySQL/InnoDB, and PostgreSQL for a greenfield system, or planning a migration between them, from explicit semantic, workload, operational, JVM-driver, DDL, cost, and team constraints. Use when an ADR, proof of concept, compatibility inventory, shadow validation, or reversible cutover is needed. Not a generic product ranking or live query-tuning workflow.developmentsqlexpressVotes: 0GitHub stars: 2
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Database Bulk LoadingADesigning and diagnosing high-volume database ingestion from the JVM across PostgreSQL, MySQL, and SQL Server: JDBC batching and statement rewrite, native COPY/LOAD DATA/Bulk Copy, staging, transaction and partial-error semantics, idempotent restart, upsert races, logging, parallelism, and post-load validation. Use when a backfill, import, migration, or batch window is too slow or unsafe. Not routine ORM fetch/write tuning, which belongs to orm-fetch-and-batching-performance.developmentrustgoVotes: 0GitHub stars: 2
Data Source PatternsAChoosing how code reaches the database — Table Data Gateway, Row Data Gateway, Active Record or Data Mapper — from the shape of the domain logic rather than from framework habit, and knowing what each one couples together. Use when a new module's persistence approach is being chosen, when entities carry both business rules and save() methods, when JPA is being applied to a schema that fights it, when SQL is scattered through service classes, when a "DAO" layer duplicates what the ORM already ...developmentjavasqlVotes: 0GitHub stars: 2
Cpu Cache And NumaAHardware-aware Java: cache-line coherence and locality, false sharing and how it differs from lock contention, object layout measured with JOL, LongAdder versus AtomicLong, data locality in arrays and collections, and NUMA topology. Use when throughput gets **worse** as threads are added, when scaling efficiency collapses, when fields are being added to a class shared between threads, when volatile counters sit next to each other, when @Contended or padding is proposed, when -XX:+UseNUMA is b...developmentgojavaVotes: 0GitHub stars: 2
Coordinated OmissionACoordinated omission in depth: response-coupled sampling, open/closed/semi-open workload models, scheduled-versus-actual clocks, generator saturation, correction at recording time versus at generation time, HdrHistogram's recordValueWithExpectedInterval semantics, what wrk2, k6, Gatling, JMeter and Locust each actually do, and the effect on capacity numbers. Use when a load test's p99 is far better than production's for the same endpoint, when a generator misses its planned schedule, when som...developmentgojavaVotes: 0GitHub stars: 2
Continuous ProfilingADesigning and operating always-on production profiling: question-driven signal choice, permanent overhead and coverage budgets, in-process versus host collection, context-label propagation, profile schemas, storage and cardinality, retention and incident preservation, deploy-aware comparisons, trust boundaries, and evidence-quality SLOs. Use when historical CPU/allocation/lock evidence must survive an incident, when profile cost or tenant labels can grow without bound, when a backend or agent...developmentrustgoVotes: 0GitHub stars: 2
Container AwarenessAWhat the JVM actually detects inside a container: cgroup v1 versus v2 detection, ActiveProcessorCount and how a CPU quota becomes a processor count, MaxRAMPercentage and every ergonomic derived from it, GC and JIT thread counts sized from the wrong number, and verifying all of it from inside the running container. Use when a pod is OOMKilled while heap usage is well below Xmx, when a Deployment has no resources.limits or sets limits.memory equal to Xmx, when MaxRAMPercentage is pushed to 90, ...developmentrustgoVotes: 0GitHub stars: 2
Consistent HashingAStable key-to-node placement across membership changes: modulo remapping, consistent-hash rings, virtual points, rendezvous and jump hashing, collision-safe Java implementations, hash contracts, replica selection, weighting, testing and membership handoff. Use when changing node count causes a miss storm or migration, ownership is uneven, or placement relies on Object.hashCode. Does not choose the shard key (sharding-and-partitioning), repair hot keys (hot-partitions-and-rebalancing), define ...developmentgojavaVotes: 0GitHub stars: 2
Consistency ModelsAChoosing distributed consistency guarantees as an engineering decision: linearizability, sequential/causal ordering, session guarantees (read-your-writes, monotonic reads), bounded staleness and eventual convergence, stated as observable contracts rather than a false total ladder; CAP stated correctly—the choice between C and A exists only while partitioned—and PACELC, replica paths and transaction isolation boundaries. Use when a user cannot see their own write, when a read after a write ret...developmentgojavaVotes: 0GitHub stars: 2
Consensus And QuorumsACrash-fault consensus and quorum reasoning: FLP, safety versus liveness, majority 2f+1, R + W > N intersection and its limits, voter/failure-domain placement, Raft terms and why external fencing still requires resource enforcement, plus the differing read/watch contracts of etcd, ZooKeeper and Consul. Use when a cluster size is being chosen, when nodes are spread across AZs or regions, when application data or a queue is being put in etcd or ZooKeeper, when a coordination store sits on the re...developmentgojavaVotes: 0GitHub stars: 2
Connection Pool SizingASizing and diagnosing a JDBC connection pool: L = λ × W where W is connection hold time rather than query latency, the database-side ceiling, HikariCP timeouts and lifetimes, transaction boundaries and idle-in-transaction, N+1 detection, JDBC batching, and what virtual threads change. Use when choosing maximumPoolSize, when connection-timeout is 0 or 30 s, when threads wait for connections under load, when HTTP or queue calls happen inside @Transactional, when connections die silently behind ...developmentjavasqlVotes: 0GitHub stars: 2
Concurrent Collections And SynchronizersAChoosing between the members of java.util.concurrent once the family is settled, and the parameter that makes it correct: which BlockingQueue and which of its four insert and remove forms, which ConcurrentHashMap atomic replaces a compound action, copy-on-write's cost, latch versus barrier versus phaser versus semaphore, the Condition await loop, and ReentrantLock versus ReentrantReadWriteLock versus StampedLock. Use when computeIfAbsent loads from a database, when IllegalStateException "Recu...developmentjavanodeVotes: 0GitHub stars: 2
Concurrency TestingATesting concurrent Java so failures appear in CI rather than in an incident: what a passing concurrency test does and does not prove, replacing sleeps with latches and deterministic executors, explicitly exercising cancellation, interruption and timeout, stress tests that assert invariants, and soak tests that catch permit and connection leaks. Use when a test uses Thread.sleep to wait for another thread, when a concurrency test is flaky and a retry is proposed, when cancellation or timeout p...developmentjavatestingVotes: 0GitHub stars: 2
Concurrency Limiting And BulkheadsAEngineer process-local concurrency limits and bulkheads around scarce resources, with explicit admission deadlines, permit ownership, weighted work, partitioning, fairness, observability and overload validation. Distinguishes concurrency, rate and queue limits and the assumptions behind Little's Law. Use after virtual-thread migrations, during downstream saturation, or when local limits leak, over-release, double-queue or fail to compose across replicas.developmentrustjavaVotes: 0GitHub stars: 2
Concurrency DiagnosticsAEvidence-led diagnosis of deadlock, starvation, livelock, saturation, leaks and virtual-thread scheduler problems. Compares traditional platform-thread dumps, jcmd all-thread dumps, ThreadMXBean, VirtualThreadSchedulerMXBean, JFR, wall/CPU profiles and application telemetry, including each tool's visibility and consistency limits. Use when progress stops, CPU and latency disagree, tasks disappear, shutdown hangs, or a virtual-thread dump is inconclusive.developmentgojavaVotes: 0GitHub stars: 2
Component And Release BoundariesADeciding what becomes an independently releasable component — a Maven module, a JPMS module, a published library — and what that costs: the tension between reusing code and being able to release it, why a shared jar couples every service depending on it, breaking cycles between components, and judging whether a component is stable enough to depend on. Use when a `common` or `shared` module is proposed or has grown, when extracting code into a library so two services can reuse it, when a depen...developmentgojavaVotes: 0GitHub stars: 2
Completablefuture CompositionADesign and diagnose CompletionStage graphs with explicit execution, ownership, failure, timeout, cancellation, context and admission semantics. Use when a continuation runs on an I/O thread, a branch failure disappears, allOf or anyOf has the wrong policy, a timeout leaves work running, or asynchronous fan-out overloads a dependency. Distinguishes Java 17/21 APIs from Java 25 preview structured-concurrency alternatives.developmentjavanodeVotes: 0GitHub stars: 2
Compilation And Inlining LogsAReading what the JIT actually did: the columns of -XX:+PrintCompilation and its flag characters, -XX:+PrintInlining and its verdict strings, -XX:+LogCompilation with JITWatch, the -Xlog:jit+compilation and JFR forms, targeted compiler directives, and turning a refusal into a code change. Use when a hot method is suspected of not reaching tier 4, when a call site shows "too big" or another inlining refusal, when a method never appears in the compilation log at all, when someone prescribes -XX:...developmentgojavaVotes: 0GitHub stars: 2
Collaborative Feature DefinitionACo-authoring Product Features and Tech Features through focused question-and-revision rounds. For a Product Feature, separates the business definition from an optional engineering analysis owned by an architect or senior engineer, including PoCs, ADRs, contracts, and engineering premises. Use when an idea needs an agreed feature brief or an evidenced decision not to proceed, not implementation. Accepted features go to feature-engineering for validation and execution planning.developmentgogitVotes: 0GitHub stars: 2