Java Articles | Backend Study Lab

Java Aug 19, 2026 4 min read

JVM Profiling and JFR for Production Backends

Use Java 25 Flight Recorder to investigate CPU, allocation, GC, locks, I/O, and virtual threads without overstating profile evidence.

Java Aug 19, 2026 5 min read

Evidence-Based JVM Tuning and Capacity Verification

Turn JVM performance hypotheses into controlled canary changes with representative load, rollback, resource budgets, and user-outcome verification.

Java Aug 19, 2026 5 min read

G1 Garbage Collector Diagnosis and Tuning

Diagnose Java 25 G1 young, marking, mixed, evacuation, and humongous-object behavior before making minimal evidence-backed tuning changes.

Java Aug 19, 2026 4 min read

Java Heap Dumps and Memory Leak Analysis

Use Java 25 class histograms and heap dumps to test retention and memory-leak hypotheses while controlling pause, disk, and data exposure.

Java Aug 19, 2026 5 min read

JVM Garbage Collection Logs and Pause Diagnosis Explained

Read Java 25 garbage collection logs to distinguish allocation pressure, live-set growth, concurrent work, pauses, and Full GC safely.

Java Aug 19, 2026 5 min read

JVM JIT, Code Cache, and Warmup Diagnosis

Diagnose Java 25 tiered compilation, compilation queues, deoptimization, code cache pressure, warmup, JFR, and AOT profile boundaries.

Java Aug 19, 2026 4 min read

JVM Native Memory, Metaspace, and Container OOM Diagnosis

Separate Java heap, HotSpot native memory, metaspace, buffers, stacks, RSS, and container OOM evidence with Java 25 NMT.

Java Aug 19, 2026 4 min read

JVM Thread Dumps, Safepoints, and CPU Saturation Diagnosis

Diagnose Java 25 platform and virtual threads, locks, safepoints, CPU saturation, pinning, and dependency waits with bounded evidence.

Java Aug 19, 2026 5 min read

Production JVM Performance Diagnostics Explained

Diagnose production JVM performance from user impact through CPU, garbage collection, memory, threads, containers, and durable outcomes.

Java Aug 19, 2026 5 min read

ZGC Low-Latency Garbage Collection Diagnosis and Tuning

Diagnose generational ZGC allocation headroom, concurrent work, stalls, heap sizing, and latency-throughput tradeoffs on Java 25.

Java Aug 18, 2026 4 min read

CompletableFuture Composition, Errors, and Timeouts

Compose Java CompletableFuture stages deliberately across executors, failures, timeouts, cancellation, context, and external side-effect boundaries.

Java Aug 18, 2026 5 min read

Java Concurrency for Backend Systems Explained

Build a practical model of tasks, threads, shared state, race conditions, thread safety, and bounded concurrency in Java backend services.

Java Aug 18, 2026 6 min read

Java Concurrency Budget Lab: Queues, Virtual Threads, and Cancellation

Run six deterministic Java concurrency scenarios to compare fixed pools, virtual threads, resource guards, deadlines, and cooperative cancellation.

Java Aug 18, 2026 4 min read

ExecutorService, Thread Pools, and Work Queues in Java

Design Java executors around admission, worker, queue, rejection, shutdown, and downstream capacity instead of treating threads as free throughput.

Java Aug 18, 2026 4 min read

Java Interruption, Cancellation, and Deadlines Explained

Propagate Java interruption and request deadlines cooperatively across executors, blocking calls, cleanup, Spring boundaries, and durable effects.

Java Aug 18, 2026 4 min read

Java Memory Model, Visibility, and Happens-Before Explained

Understand atomicity, visibility, ordering, data races, volatile fields, safe publication, and happens-before reasoning in Java backend code.

Java Aug 18, 2026 4 min read

Scoped Values and Structured Concurrency in Modern Java

Separate Java 25 Scoped Values from JDK 26 preview Structured Concurrency and reason about bounded context, task lifetime, failure, and cancellation.

Java Aug 18, 2026 5 min read

Java Virtual Threads for Backend Services

Use Java 21 virtual threads for blocking backend tasks while keeping CPU, connection pools, downstream limits, context, and pinning explicit.

Java Aug 18, 2026 5 min read

Production Java Concurrency Troubleshooting

Diagnose Java thread starvation, unbounded queues, lock contention, virtual-thread pinning, downstream overload, and failed cancellation with evidence.

Java Aug 18, 2026 5 min read

synchronized, Locks, and Atomic Variables in Java

Compare Java monitors, ReentrantLock, CAS, atomic variables, lock scope, fairness, and compound invariants through backend examples.

Java Jul 1, 2026 5 min read

HashMap Collision Handling Explained

Learn how HashMap collision handling works in Java, including buckets, hashCode, equals, tree bins, load factor, bad keys, and performance.

Java Jul 1, 2026 5 min read

Java equals and hashCode Explained

Learn Java equals and hashCode contracts, why they matter for HashMap and HashSet, common mistakes, records, mutability, and testing.

Java Jun 30, 2026 4 min read

HashSet vs TreeSet in Java

Compare HashSet and TreeSet in Java by ordering, uniqueness, contains performance, null handling, memory cost, and practical backend use cases.

Java Jun 30, 2026 4 min read

Queue vs Deque in Java

Compare Queue and Deque in Java, including FIFO queues, double-ended operations, ArrayDeque, LinkedList, stack usage, and practical backend defaults.

Java Jun 30, 2026 4 min read

TreeMap vs HashMap in Java

Compare TreeMap and HashMap in Java by key ordering, lookup complexity, range queries, null handling, memory overhead, and backend use cases.

Java May 10, 2026 6 min read

Time Complexity of Java Collections

A practical reference for Java collection time complexity, including ArrayList, LinkedList, HashMap, TreeMap, HashSet, and PriorityQueue.

Java Mar 15, 2026 4 min read

ConcurrentHashMap Explained

A practical explanation of ConcurrentHashMap in Java, including thread safety, atomic methods, iteration behavior, and common mistakes.

Java Mar 8, 2026 4 min read

HashMap Load Factor Explained

Learn what HashMap load factor means in Java, how it affects resizing, memory usage, collision risk, and lookup performance.

Java Mar 1, 2026 4 min read

ArrayList vs LinkedList in Java

Compare ArrayList and LinkedList in Java by access patterns, insertion cost, memory overhead, and practical backend usage.

Java Jan 14, 2026 4 min read

Java PriorityQueue Explained with Practical Examples

Learn how Java PriorityQueue works, when to use it, how ordering is defined, and common pitfalls around iteration and custom comparators.

Java Jan 8, 2026 4 min read

HashMap vs Hashtable in Java: Key Differences

Compare HashMap and Hashtable in Java, including synchronization, null keys, performance, legacy status, and modern alternatives.