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JD Tech Talk

Jun 6, 2025 · Backend Development

Upgrade Java Projects to JDK 21: Challenges, Solutions & Best Practices

This article outlines the motivations, challenges, and step‑by‑step solutions for migrating over 100 Java applications to JDK 21, covering dependency conflicts, module system adjustments, Maven plugin compatibility, garbage‑collector selection, and practical build and deployment practices to ensure a smooth upgrade.

Backend DevelopmentGarbage CollectionJDK21

0 likes · 13 min read

Upgrade Java Projects to JDK 21: Challenges, Solutions & Best Practices

DaTaobao Tech

Apr 2, 2025 · Backend Development

Understanding Java Virtual Threads: From Traditional Thread Models to Stackful Coroutines

The article traces Java’s concurrency evolution from heavyweight thread‑per‑request and complex reactive models to JDK 21’s virtual threads, which act as stack‑ful coroutines offering lightweight, heap‑allocated threads, full stack traces, and blocking‑I/O compatibility while preserving the familiar thread API.

Async ProgrammingConcurrencyJDK21

0 likes · 24 min read

Understanding Java Virtual Threads: From Traditional Thread Models to Stackful Coroutines

Architecture Digest

Sep 18, 2024 · Fundamentals

New Features in JDK 21: Virtual Threads, Sequenced Collections, String Templates, Record Patterns, and Switch Pattern Matching

The article introduces JDK 21’s latest long‑term‑support features—including virtual threads, sequenced collections, preview string templates, record patterns, and switch pattern matching—explaining their concepts, benefits, and providing concrete Java code examples for each.

JDK21JavaRecordPatterns

0 likes · 14 min read

New Features in JDK 21: Virtual Threads, Sequenced Collections, String Templates, Record Patterns, and Switch Pattern Matching

DaTaobao Tech

Aug 28, 2024 · Backend Development

Understanding Java Virtual Threads: Principles, Implementation, and Performance

Java virtual threads, introduced in JDK 21, decouple Java threads from OS threads by using continuations and a ForkJoinPool scheduler, allowing millions of cheap, blocking‑friendly threads that boost throughput and simplify concurrent code compared to traditional platform threads or reactive frameworks, as demonstrated by performance benchmarks.

ConcurrencyJDK21Java

0 likes · 23 min read

Understanding Java Virtual Threads: Principles, Implementation, and Performance

Zhuanzhuan Tech

Aug 23, 2024 · Backend Development

Upgrading to JDK 21 and Adopting Generational ZGC: Motivation, Design, Implementation, Monitoring, and Performance Evaluation

This article explains why the backend services were upgraded from JDK 8 to JDK 21, introduces the generational ZGC garbage collector, details its architecture, tuning parameters, integration steps, monitoring setup, and presents performance test results that demonstrate reduced allocation stalls, lower latency, higher throughput, and near‑zero GC pauses.

Garbage CollectionGenerational ZGCJDK21

0 likes · 20 min read

Upgrading to JDK 21 and Adopting Generational ZGC: Motivation, Design, Implementation, Monitoring, and Performance Evaluation

Spring Full-Stack Practical Cases

Jun 5, 2024 · Backend Development

Unlock Massive Concurrency: How Java Virtual Threads Transform Backend Development

This article explains Java virtual threads, contrasting them with platform threads, and shows how to create, schedule, and use them effectively with Thread.Builder and Executors to achieve high‑throughput, low‑latency server applications while avoiding common pitfalls like pooling and pinning.

Backend DevelopmentConcurrencyJDK21

0 likes · 14 min read

Unlock Massive Concurrency: How Java Virtual Threads Transform Backend Development

Sohu Tech Products

May 21, 2024 · Backend Development

Debugging java.net.spi.InetAddressResolverProvider SPI Failure with OpenTelemetry Java Agent in Spring Boot

The article explains how a custom java.net.spi.InetAddressResolverProvider SPI that works in a regular Spring Boot 3.x JAR fails when the OpenTelemetry Java agent is added because the agent’s JarLoader cannot read the SPI configuration inside the BOOT‑INF layout, and resolves the issue by disabling the agent’s own resolver resource so the custom provider is used.

JDK21JavaOpenTelemetry

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Debugging java.net.spi.InetAddressResolverProvider SPI Failure with OpenTelemetry Java Agent in Spring Boot

Spring Full-Stack Practical Cases

May 13, 2024 · Fundamentals

Unlock Java 21: Master Record Patterns, Switch Enhancements, and New Templates

This article explains Java 21’s preview features—including record patterns, enhanced switch expressions, virtual threads, string template processors, sequenced collections, and unnamed patterns—showing how they simplify type checks, pattern matching, and code readability with practical code examples.

JDK21JavaRecord Patterns

0 likes · 18 min read

Unlock Java 21: Master Record Patterns, Switch Enhancements, and New Templates

Architect

Feb 1, 2024 · Backend Development

Design and Optimization of Trace2.0: A High‑Performance Backend Tracing System

Trace2.0 is an OpenTelemetry‑based application monitoring system that processes petabyte‑scale trace data using multi‑channel client protocols, gRPC, load‑balancing optimizations, ZSTD compression, Kafka pipelines, ClickHouse storage, and a JDK 21 upgrade with virtual threads, achieving significant performance and cost improvements.

ClickHouseJDK21Kafka

0 likes · 15 min read

Design and Optimization of Trace2.0: A High‑Performance Backend Tracing System

macrozheng

Oct 27, 2023 · Backend Development

Unlock 20× Faster Java Concurrency with JDK21 Virtual Threads

This article explains JDK21's new virtual threads, compares them with traditional thread pools through a 10,000‑thread benchmark, shows over 20‑fold performance gains, and provides practical code examples and configuration tips for Java developers.

Backend DevelopmentJDK21Java Concurrency

0 likes · 8 min read

Unlock 20× Faster Java Concurrency with JDK21 Virtual Threads

Selected Java Interview Questions

Oct 10, 2023 · Fundamentals

New Features in Java 21: Project Amber, Loom, Panama, and Core Library Enhancements

Java 21, released on September 19 as a long‑term‑support release with eight years of Oracle support, introduces fifteen JEPs—including preview string templates, record patterns, switch pattern matching, virtual threads, scoped values, structured concurrency, foreign function & memory APIs, and a new sequenced‑collection interface—along with numerous performance, security, and deprecation updates, all illustrated with code examples.

JDK21JavaProject Amber

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New Features in Java 21: Project Amber, Loom, Panama, and Core Library Enhancements

macrozheng

Sep 20, 2023 · Fundamentals

Why JDK 21’s Virtual Threads Could Revolutionize Java Concurrency

The article announces the official GA release of JDK 21, explains common version labels such as Alpha, Beta, RC and LTS, highlights the standout Virtual Threads feature requiring minimal code changes, and reviews the fifteen new JEPs across core libraries, language specifications, HotSpot and security enhancements.

JDK21JavaJavaFeatures

0 likes · 12 min read

Why JDK 21’s Virtual Threads Could Revolutionize Java Concurrency

Architecture Digest

Jun 16, 2023 · Backend Development

Generational Shenandoah GC Feature Removed from Java 21

Java 21, slated for release on September 19, 2023 as the next LTS version after Java 17, will drop the experimental Generational Shenandoah garbage‑collector feature during its Ramp‑down phase due to insufficient readiness, with the change slated for removal by the June 14 review deadline.

Garbage CollectionGenerational GCJDK21

0 likes · 4 min read

Generational Shenandoah GC Feature Removed from Java 21