Java (Modern JDK)

Java Amber Project

Language ergonomics. Records, patterns, etc.

Java Annotations

How Java annotations provide metadata for frameworks, tooling, and compile-time processing.

AssertJ

Chained + readable.

async-profiler

Low-overhead sampling.

Java Atomic Classes

AtomicInteger, AtomicReference etc.

Bazel

Reproducible + scalable.

Java BlockingQueue

Producer-consumer.

Java Class Data Sharing (CDS)

AppCDS speeds startup.

JVM class loading architecture

Deep-dive on JVM class loading: bootstrap/platform/application loaders and parent delegation, the load-verify-prepare-resolve-initialize pipeline, (na…

Java Collections Framework

The Java Collections Framework: List, Set, Map interfaces and their common implementations (ArrayList, HashMap, TreeSet).

Java Collectors

Terminal reduce operations.

Java CompletableFuture

Async composition.

Java Concurrency

Java's concurrency toolkit: threads, synchronized, locks, atomics, executors, and the java.util.concurrent package.

Java ConcurrentHashMap

Lock-free reads. Scoped writes.

Java Containerization

Sizing + JVM in containers.

Java CountDownLatch

Wait for N events.

Java Deprecation + Removals

Nashorn, applets, SecurityManager.

Dropwizard

Opinionated JSON API framework.

Java Enhanced For Loop

for (var e : coll). Iterable.

Java Epsilon GC

No-op collector.

Java ExecutorService

Thread pool. Submit + shutdown.

Java Foreign Function + Memory API (Panama)

Native interop. Java 22+.

Java FFM API

How Java's Foreign Function and Memory (FFM) API provides safe native interop.

Java FFM architecture

Deep-dive on the Foreign Function & Memory API: confined vs shared vs automatic arenas, MemorySegment bounds and liveness checks, layo…

Java ForkJoinPool

Work-stealing pool.

Java Function + Predicate + Consumer + Supplier

Standard FIs.

Java Functional Interfaces

@FunctionalInterface. Single abstract method.

Java G1 Garbage Collector

Modern default. Region-based.

Java GC Algorithms

The main JVM GC algorithms, their pause characteristics, and when to use each.

JVM GC architecture

Deep-dive on JVM garbage collectors: regions + TLABs + write barriers, per-collector strategies, tuning and observability.

Java GC Logs

-Xlog:gc option.

Java Generics

How Java generics work: type parameters, bounded types, wildcards, and the reality of type erasure.

Java Generics Improvements

Diamond operator + wildcard.

GraalVM Architecture in Depth

A 2500-word walkthrough of GraalVM: compiler, Native Image AOT, instant startup, low memory, reflection config, Truffle polyglot, framework support.

Java GraalVM Native Image

Ahead-of-time compilation.

Gradle

Groovy/Kotlin DSL build.

Java Heap Tuning

Xmx + Xms + GC choice.

Helidon

Oracle's cloud-native Java.

Hibernate + JPA

ORM. Historic dominance.

HotSpot vs GraalVM

Runtime comparison.

Java HttpClient

How Java 11's HttpClient replaces older HttpURLConnection.

Java instanceof Pattern Matching

Bind + check in one expression.

Jakarta EE (was Java EE)

Enterprise Java spec.

Java Flight Recorder (JFR)

Low-overhead profiling.

Java Flight Recorder -- always-on, low-overhead profiling

Deep-dive on Java Flight Recorder (JFR): continuous event recording, JFR events (GC/allocation/locks/IO), very low overhead (<1…

JVM JIT architecture

Deep-dive on JVM JIT: interpreter, C1, C2, Graal, tiered compilation, inline caches, escape analysis, deoptimization, code cache, diagnostics.

Java JIT Compiler (C1/C2)

Tiered compilation.

JITWatch

See JIT decisions.

Java jlink

Create minimal runtime.

jOOQ

SQL as Java DSL.

Java jpackage

MSI, DMG, DEB, RPM installers.

JUnit 5 (Jupiter)

Modern Java testing standard.

JVM Garbage Collection Architecture in Depth

A 2500-word walkthrough of JVM GC: application threads, generational heap, G1, ZGC, Shenandoah, write barriers, TLABs, and observability.

JVM Memory Model

How JVM memory is organized: heap generations, stack per thread, metaspace for class metadata, and off-heap for direct buffers.

Java JVMTI + Instrumentation API

Attach agents for profiling/monitoring.

Java Lambda Expressions

How Java lambdas work, functional interfaces, method references, and how they enable functional-style APIs.

Java Lambdas

Anonymous functions. Java 8+.

Project Leyden architecture

Deep-dive on Project Leyden: AOT compilation, startup improvement, condensers, class data cache, compatibility, vs Native Image.

Java LTS Releases

8, 11, 17, 21, 25.

MapStruct

Code-gen mapping between DTOs.

Apache Maven

Standard Java build.

Java Memory Model -- happens-before, visibility, and data races

Deep-dive on the Java Memory Model: the visibility/ordering problem from caches and reordering, happens-before, volatile/synchronized/final/atomics es…

Java MethodHandles + VarHandle

Modern reflection alternative.

Java Method References

::syntax for lambdas.

Micrometer

Metrics facade for Java.

Micronaut

Compile-time DI. Fast + minimal.

Mockito

Modern default mocking.

Java Module System (JPMS)

Java 9+. Modularity via module-info.java.

Java Modules

How the Java Platform Module System (JPMS) provides strong encapsulation for large codebases.

MyBatis

XML + annotation SQL mapping.

GraalVM native image architecture

Deep-dive on GraalVM native image: AOT compilation, closed-world analysis, reflection config, metadata repo, build modes, trade-offs.

Java NIO and Netty

Deep-dive on Java NIO and Netty: selector-driven non-blocking IO, event loops and handler pipelines, codecs for framing, pooled off-heap ByteBuffers, …

OpenJDK Vendors

Oracle, Corretto, Temurin, Zulu.

OpenTelemetry Java

Traces + metrics + logs.

Java Optional

Null-safe wrapper.

Java Overview

What Java is, why the JVM matters, and where Java fits in modern computing after 25+ years.

Java OWASP Dependency Check

Vuln scanning.

Java Parallel GC

Throughput-focused.

Java Parallel Streams

ForkJoinPool.commonPool.

Java Pattern Matching

How Java's pattern matching (instanceof, switch) destructures and binds in one expression.

Java pattern matching architecture

Deep-dive on Java pattern matching: sealed interfaces, records, switch expressions, type + record patterns, guards, exhaustiveness.

Java Phaser

Reusable multi-phase barrier.

Play Framework (Java)

Reactive full-stack. Also Scala.

Project Amber

What Project Amber delivers: records, sealed, pattern matching, and more.

Project Babylon

How Project Babylon extends Java reflection for AI + accelerator use.

Project Leyden

How Project Leyden aims to reduce Java startup time via ahead-of-time compilation.

Project Lilliput

How Project Lilliput reduces Java object header size for memory savings.

Project Loom

How Project Loom brought virtual threads and structured concurrency to Java.

Project Panama

How Panama provides safer, faster JNI replacement for calling native code from Java.

Project Valhalla

How Project Valhalla aims to bring value types and specialized generics to Java.

Java Project Valhalla Architecture in Depth

A 2500-word walkthrough of Java Project Valhalla: value classes, layout, nullability, generic specialization, migration, escape analysis, performance.

Project Valhalla Status

The current status of Project Valhalla: value types delivery.

Java Prometheus Monitoring

Micrometer + Actuator.

Quarkus

Cloud-native Java. GraalVM-friendly.

Java Records

How records provide concise immutable data classes in modern Java.

Java records architecture

Deep-dive on Java records: declaration, auto members, immutability, compact ctor, pattern matching, sealed, serialization, interop.

Java ReentrantLock

Lock class with more features than synchronized.

Java Reflection

How Java reflection inspects classes and invokes methods dynamically at runtime.

Java Scoped Values

How ScopedValue provides context sharing better than ThreadLocal for virtual threads.

Java Sealed Classes

How sealed classes restrict subclasses to a known set, enabling exhaustive pattern matching.

Java Sealed Classes

Restrict inheritance. Foundation of ADTs.

Java Semaphore

Count-based access limiter.

Java Serial GC

Single-threaded. Small apps.

Java Shenandoah GC

Alternative low-pause.

Spring Boot

Opinionated Spring. Auto-config.

Spring Data

Repository abstraction.

Spring Framework

DI + AOP + Web. Dominant Java.

Spring Security

Auth + authz framework.

java_stream_gatherers

Java Stream

Core operations.

Java Streams API

Functional collection processing.

Java Streams API

How the Streams API enables functional-style data processing in Java: filter, map, collect, reduce, and parallel streams.

Java string dedup architecture

Deep-dive on Java string deduplication: G1 dedup background scan, compact strings, intern(), dedup table, cost, metrics.

Java String Templates

Preview. STR."...\{var}..."

Java Structured Concurrency

How structured concurrency provides bounded, hierarchical concurrent execution.

Java StructuredTaskScope

Preview. Correlated task groups.

Java Switch Expressions

Arrow syntax + returns value.

Java synchronized Keyword

Intrinsic locks. Simple + limited.

Testcontainers

Real Postgres/Kafka/etc in tests.

Java Text Blocks

Triple-quote multiline strings.

Java ThreadLocal

Per-thread storage.

java.util.function Package

Rich set of functional interfaces.

Project Valhalla architecture

Deep-dive on Project Valhalla: value classes, primitive classes, flat layout, generic specialization, nullability, migration.

Java Valhalla Project

Value types. Future feature.

Java var

Local variable inference. Java 10+.

Java Vector API

SIMD via API. Preview.

Vert.x

Reactive polyglot toolkit.

Java Virtual Threads

How virtual threads (Project Loom) enable massive concurrency without OS thread costs.

Java Virtual Threads Architecture in Depth

A 2500-word walkthrough of Java Virtual Threads: application code, carriers, continuations, scheduler, blocking I/O, pinning, ReentrantLock, structure…

Java Virtual Threads Deep

Loom preview then final.

VisualVM

Open-source JVM monitoring.

Java volatile Keyword

Memory visibility. No atomicity.

WireMock

Simulate external APIs.

YourKit + JProfiler

Commercial JVM profilers.

Java ZGC

Sub-10ms pauses. Very large heaps.