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Java 21

48 articles · Page 1 of 1
Programmer XiaoFu
Programmer XiaoFu
Jul 16, 2026 · Backend Development

Can Java 21 Virtual Threads Replace CompletableFuture for Async Programming?

With Java 21’s virtual threads making threads cheap, the article examines whether the traditional CompletableFuture async style can be dropped, showing that simple IO can now be written synchronously, while complex task orchestration, fallback, and timeout still benefit from CompletableFuture’s richer API.

Async ProgrammingCompletableFutureJava 21
0 likes · 10 min read
Can Java 21 Virtual Threads Replace CompletableFuture for Async Programming?
Su San Talks Tech
Su San Talks Tech
Jun 1, 2026 · Backend Development

Can Java 21’s Virtual Threads Make Thread Pools Obsolete?

The article examines whether Java 21’s cheap virtual threads can replace traditional thread pools, explaining the original purpose of pools, their role as natural throttlers, scenarios where virtual threads excel or fail, and practical guidelines to avoid pitfalls like pinning.

Java 21Thread PoolVirtual Threads
0 likes · 7 min read
Can Java 21’s Virtual Threads Make Thread Pools Obsolete?
Spring Full-Stack Practical Cases
Spring Full-Stack Practical Cases
May 22, 2026 · Fundamentals

Upgrade from Java 8: 8 Powerful Features in Java 21 You Should Know

The article examines why many projects still cling to Java 8 and demonstrates eight transformative Java 21 features—including records, sealed classes, pattern‑matching for instanceof, switch expressions, text blocks, virtual threads, structured concurrency, and enhanced APIs—showing code examples and the benefits they bring to performance, readability, and maintainability.

Java 21RecordsSealed Classes
0 likes · 11 min read
Upgrade from Java 8: 8 Powerful Features in Java 21 You Should Know
Programmer1970
Programmer1970
May 20, 2026 · Fundamentals

Only 5 of Java 21’s 15 New Features Actually Change Your Code

Java 21, the latest LTS release, adds fifteen JEPs but only five—virtual threads, record patterns, switch pattern matching, string templates, and sequenced collections—significantly alter coding style, offering lightweight concurrency, concise data deconstruction, modern switch syntax, powerful string interpolation, and enhanced collection APIs.

Java 21Record PatternsSequenced Collections
0 likes · 8 min read
Only 5 of Java 21’s 15 New Features Actually Change Your Code
Java Tech Enthusiast
Java Tech Enthusiast
May 6, 2026 · Backend Development

Spring Boot 4.1’s Default Virtual Threads Boost Throughput—But Require HikariCP Tuning

Spring Boot 4.1 makes virtual threads the default, dramatically increasing I/O concurrency, yet the unchanged HikariCP maximumPoolSize can exhaust connections; the article explains this incompatibility, shows how to adjust pool settings, enable lazy connections, and outlines a step‑by‑step migration path from 3.x to 4.1.

HikariCPJava 21LazyConnection
0 likes · 19 min read
Spring Boot 4.1’s Default Virtual Threads Boost Throughput—But Require HikariCP Tuning
LuTiao Programming
LuTiao Programming
Apr 22, 2026 · Fundamentals

Stop Memorizing Design Patterns: Modern Strategy Pattern with Java 21+ Sealed Interfaces and Pattern Matching

The article critiques the classic interface‑plus‑N‑implementations Strategy Pattern for causing class explosion, then demonstrates how Java 17’s sealed interfaces and records together with Java 21’s pattern‑matching switch provide a more concise, type‑safe, and maintainable modern implementation.

Design PatternsJava 21Pattern Matching
0 likes · 7 min read
Stop Memorizing Design Patterns: Modern Strategy Pattern with Java 21+ Sealed Interfaces and Pattern Matching
LuTiao Programming
LuTiao Programming
Mar 3, 2026 · Backend Development

From Java 21 to 25: Full Guide to Upgrading Spring Boot 3.5 → 4.0

This article explains why staying on old Java and Spring Boot versions is risky, introduces a dual‑axis model for the upgrade, details Java 21‑to‑25 language and JVM improvements, outlines Spring Boot 3.5‑to‑4.0 structural changes, and provides a step‑by‑step manual and OpenRewrite migration workflow with verification guidelines.

Java 21Java 25Migration
0 likes · 11 min read
From Java 21 to 25: Full Guide to Upgrading Spring Boot 3.5 → 4.0
JakartaEE China Community
JakartaEE China Community
Feb 9, 2026 · Backend Development

Eclipse Foundation Unveils Jakarta EE 11 with Simplified Data Access and Cloud‑Native Enhancements

The Eclipse Foundation announced Jakarta EE 11, highlighting streamlined data access via the new Jakarta Data spec, support for Java 21 including virtual threads, modernized testing tools, deprecation of Managed Beans, and early certification of several enterprise servers, marking a major step toward cloud‑native Java development.

Cloud NativeEnterprise JavaJakarta Data
0 likes · 6 min read
Eclipse Foundation Unveils Jakarta EE 11 with Simplified Data Access and Cloud‑Native Enhancements
JavaGuide
JavaGuide
Oct 16, 2025 · Backend Development

Why Upgrading from Java 8 to Java 21 Boosts Development Efficiency

The article walks through the evolution from Java 8 to Java 21, comparing preview and standard features such as pattern‑matching instanceof, switch expressions, text blocks, the new HttpClient API, var type inference, virtual threads, records, immutable collections, improved try‑with‑resources, sequenced collections, and garbage‑collector enhancements, illustrating each with concrete code examples and practical recommendations.

Java 21Pattern MatchingRecord
0 likes · 16 min read
Why Upgrading from Java 8 to Java 21 Boosts Development Efficiency
JakartaEE China Community
JakartaEE China Community
Oct 14, 2025 · Fundamentals

What Changed in Java 21? A Complete API Comparison for Upgrading from Java 17

This article provides a detailed comparison of Java 17 and Java 21 APIs, listing deprecated and removed features, suggested replacements, new I/O and serialization capabilities, enhanced reflection, Unicode emoji support, the preview foreign memory API, and the Generational ZGC, illustrated with real‑world code examples and usage scenarios.

API changesGarbage CollectionJava 21
0 likes · 15 min read
What Changed in Java 21? A Complete API Comparison for Upgrading from Java 17
Architecture Digest
Architecture Digest
Apr 27, 2025 · Backend Development

Using Java 21 Virtual Threads in Spring Boot: Basics, Performance Comparison, and Best Practices

This article introduces Java 21 virtual threads, explains their lightweight and high‑concurrency advantages, demonstrates basic and delayed creation, shows how to enable them in Spring Boot with minimal configuration, compares performance against traditional threads, and provides additional Java performance optimization tips.

Java 21Spring BootVirtual Threads
0 likes · 6 min read
Using Java 21 Virtual Threads in Spring Boot: Basics, Performance Comparison, and Best Practices
Architecture Digest
Architecture Digest
Mar 5, 2025 · Backend Development

Understanding Java Virtual Threads and Their Performance Benefits in Spring Boot

This article introduces Java 21's virtual threads, explains their lightweight and high‑concurrency advantages, demonstrates basic and delayed usage with code examples, shows how to enable them in Spring Boot, compares performance against traditional threads, and offers additional Java performance‑tuning techniques.

Java 21Spring BootVirtual Threads
0 likes · 7 min read
Understanding Java Virtual Threads and Their Performance Benefits in Spring Boot
DaTaobao Tech
DaTaobao Tech
Jan 6, 2025 · Backend Development

Java 21 LTS Features Overview and Practical Guide

This article walks readers through upgrading from Java 11 to the Java 21 LTS by explaining the six‑month release cadence, JEP process, and SDKman setup, then demonstrates practical code examples for twelve new features—including preview Unnamed Classes, String Templates, Scoped Values, Structured Concurrency, Vector API, Virtual Threads, and Generational ZGC—highlighting their motivations, benefits, and production considerations.

JDK LTSJVMJava 21
0 likes · 16 min read
Java 21 LTS Features Overview and Practical Guide
Architecture Digest
Architecture Digest
Dec 26, 2024 · Backend Development

Understanding Java 21 Virtual Threads: Basics, Spring Boot Integration, and Performance Comparison

This article introduces Java 21 virtual threads, explains their lightweight, high‑concurrency and automatic management advantages, demonstrates basic and delayed usage with code examples, shows how to enable them in Spring Boot, and compares their performance against traditional threads in various scenarios.

Java 21Spring BootVirtual Threads
0 likes · 7 min read
Understanding Java 21 Virtual Threads: Basics, Spring Boot Integration, and Performance Comparison
Architecture Digest
Architecture Digest
Dec 10, 2024 · Backend Development

Understanding Java Virtual Threads and Their Use in Spring Boot

This article explains Java 21's virtual threads, their lightweight and high‑concurrency advantages, demonstrates basic creation and Spring Boot integration, compares performance against traditional threads, and offers additional Java performance optimization techniques.

Java 21Spring BootVirtual Threads
0 likes · 7 min read
Understanding Java Virtual Threads and Their Use in Spring Boot
JavaEdge
JavaEdge
Mar 22, 2024 · Fundamentals

What’s New in IntelliJ IDEA 2023.3? AI Assistant, Java 21, and Built‑in Kubernetes

IntelliJ IDEA 2023.3 introduces a production‑ready AI Assistant, full Java 21 support with virtual threads and pattern‑matching switch, a Run‑to‑Cursor debugging feature, a floating toolbar with quick edit actions, out‑of‑the‑box Kubernetes tooling, and numerous UI enhancements for a smoother developer experience.

AI assistantIDE FeaturesIntelliJ IDEA
0 likes · 8 min read
What’s New in IntelliJ IDEA 2023.3? AI Assistant, Java 21, and Built‑in Kubernetes
Java Architecture Diary
Java Architecture Diary
Feb 1, 2024 · Backend Development

Must‑Read Java 21 & Spring Boot 3.2 Resources for the Lunar New Year

Celebrating the Lunar New Year, this roundup shares essential Java 21 updates, Spring Boot 3.2 enhancements, domestic open‑source innovations, and other hand‑picked tools and articles, providing developers with quick links to explore new APIs, performance improvements, and cutting‑edge Java ecosystem resources.

Java 21NacosSpring Boot
0 likes · 5 min read
Must‑Read Java 21 & Spring Boot 3.2 Resources for the Lunar New Year
Programmer DD
Programmer DD
Jan 5, 2024 · Backend Development

How Fast Are Virtual Threads in Spring Boot 3.2 for Static File Servers?

This article evaluates the performance of Spring Boot 3.2's virtual threads when serving static files, comparing them with traditional platform threads across various concurrency levels, and concludes that platform threads slightly outperform virtual threads in this I/O‑bound scenario while suggesting better use cases for database‑driven workloads.

Java 21Spring BootStatic File Server
0 likes · 12 min read
How Fast Are Virtual Threads in Spring Boot 3.2 for Static File Servers?
Java Backend Technology
Java Backend Technology
Dec 26, 2023 · Backend Development

Exploring Spring Boot 3.2: Java 21, Virtual Threads, and GraalVM Native Images

Spring Boot 3.2 now fully supports Java 21, Project Loom virtual threads, and GraalVM native images, and this guide walks through installing Java 21‑GraalVM, configuring virtual threads, building sample controllers, async and scheduled tasks, and creating a native executable to achieve faster startup and lower memory usage.

GraalVMJava 21Native Image
0 likes · 9 min read
Exploring Spring Boot 3.2: Java 21, Virtual Threads, and GraalVM Native Images
IT Services Circle
IT Services Circle
Dec 11, 2023 · Fundamentals

JetBrains IntelliJ IDEA 2023.3 Release Highlights

The IntelliJ IDEA 2023.3 update introduces the fully launched AI Assistant, complete Java 21 support, enhanced debugging tools, a floating toolbar, out‑of‑the‑box Kubernetes integration, numerous UI improvements, faster Gradle and Maven imports, and a host of new framework and technology features.

AI assistantIDEIntelliJ IDEA
0 likes · 7 min read
JetBrains IntelliJ IDEA 2023.3 Release Highlights
Programmer DD
Programmer DD
Dec 11, 2023 · Backend Development

What’s New in IntelliJ IDEA 2023.3? Java 21 Support and AI Assistant Update

JetBrains' IntelliJ IDEA 2023.3 release brings full Java 21 support, a new Run‑to‑Cursor debugging option, floating editing toolbars, color‑coded editor tabs, refreshed macOS icons, enhanced Speed Search shortcuts, and integrates Lets‑Plot for no‑code data visualization, though the AI Assistant remains unavailable in mainland China.

Data VisualizationDebuggingIDE Features
0 likes · 5 min read
What’s New in IntelliJ IDEA 2023.3? Java 21 Support and AI Assistant Update
Architecture Digest
Architecture Digest
Nov 29, 2023 · Backend Development

Exploring Spring Boot 3.2 with Java 21, GraalVM Native Images, and Virtual Threads

This article demonstrates how Spring Boot 3.2 fully supports Java 21, Project Loom virtual threads, and GraalVM native images, providing step‑by‑step instructions, configuration details, and runnable code examples that showcase building, running, and profiling a Spring Boot application with these modern technologies.

GraalVMJava 21Native Image
0 likes · 8 min read
Exploring Spring Boot 3.2 with Java 21, GraalVM Native Images, and Virtual Threads
Programmer DD
Programmer DD
Nov 24, 2023 · Backend Development

What’s New in Spring Boot 3.2? Explore Java 21 Features and Virtual Threads

Spring Boot 3.2, released shortly after Java 21, brings a host of enhancements such as virtual thread support, CRaC checkpoint restore, SSL bundle reloading, improved observability, new RestClient and JdbcClient, Jetty 12, Pulsar, Kafka and RabbitMQ SSL, redesigned nested JAR handling, Docker image build upgrades, and a comprehensive video walkthrough by Josh Long.

DockerJava 21Kafka
0 likes · 7 min read
What’s New in Spring Boot 3.2? Explore Java 21 Features and Virtual Threads
Alibaba Cloud Native
Alibaba Cloud Native
Oct 25, 2023 · Backend Development

Unlock Java 21: Virtual Threads, Generational ZGC, and ARMS Monitoring Guide

This article introduces Java 21’s major enhancements—including lightweight virtual threads and generational ZGC—provides code samples for creating virtual threads and enabling ZGC, demonstrates a Spring Boot 3.x application using record patterns, and explains how to monitor Java 21 services with Alibaba Cloud ARMS on ACK.

ARMS MonitoringGenerational ZGCJava 21
0 likes · 12 min read
Unlock Java 21: Virtual Threads, Generational ZGC, and ARMS Monitoring Guide
Programmer DD
Programmer DD
Oct 13, 2023 · Fundamentals

Enable Java 21 Preview Features in IntelliJ IDEA 2023.2

This guide explains how to enable Java 21 preview features in IntelliJ IDEA 2023.2 by configuring compiler and runtime options, allowing developers to experiment with upcoming language capabilities such as unnamed classes, patterns, and virtual threads.

ConfigurationIDEAJava 21
0 likes · 3 min read
Enable Java 21 Preview Features in IntelliJ IDEA 2023.2
Programmer DD
Programmer DD
Oct 4, 2023 · Fundamentals

How to Enable Java 21 Preview Features in IntelliJ IDEA 2023.2

This guide explains why Java preview features are disabled by default, and provides step‑by‑step instructions with screenshots for configuring IntelliJ IDEA 2023.2 to enable the --enable-preview flag so you can run and test Java 21 preview language features.

IDE configurationIntelliJ IDEAJava 21
0 likes · 3 min read
How to Enable Java 21 Preview Features in IntelliJ IDEA 2023.2
Programmer DD
Programmer DD
Sep 28, 2023 · Backend Development

Master Java 21 Virtual Threads: Creation, Usage, and Best Practices

This article explains Java 21's virtual threads, their lightweight nature, and provides step‑by‑step code examples for creating and managing them via static builders, ExecutorService, and thread factories, helping developers improve concurrency and scalability in Java applications.

Java 21Thread APIVirtual Threads
0 likes · 6 min read
Master Java 21 Virtual Threads: Creation, Usage, and Best Practices
Programmer DD
Programmer DD
Sep 25, 2023 · Backend Development

Discover Java 21’s New repeat() Method for StringBuilder and StringBuffer

Java 21 introduces repeat() overloads for StringBuilder and StringBuffer, allowing you to duplicate characters or CharSequence efficiently; the article demonstrates usage with sample code, explains the Unicode codePoint variant, and invites readers to explore creative applications of this new API.

Code ExampleJava 21StringBuffer
0 likes · 2 min read
Discover Java 21’s New repeat() Method for StringBuilder and StringBuffer
21CTO
21CTO
Sep 24, 2023 · Backend Development

Why Java 21 Is Driving the Surge in Spring Cloud Adoption

Oracle's Java 21 release introduces virtual threads, record patterns, ordered collections and a preview FFM API, while Eclipse survey data shows rising Spring and Spring Boot usage and accelerating cloud‑native adoption among Java developers.

Cloud NativeJava 21Spring Boot
0 likes · 5 min read
Why Java 21 Is Driving the Surge in Spring Cloud Adoption
Java Architecture Diary
Java Architecture Diary
Sep 21, 2023 · Backend Development

Unlock Java 21: New Features, Virtual Threads, and Migration Tips

Java 21, the latest LTS release, introduces virtual threads, sequenced collections, record patterns, and other enhancements; the article explains these new features, guides developers on configuring IDEs and runtimes with Azul Zulu and IntelliJ IDEA, and resolves Lombok incompatibility by updating to version 1.18.30.

Java 21LombokSpring Boot
0 likes · 4 min read
Unlock Java 21: New Features, Virtual Threads, and Migration Tips
Programmer DD
Programmer DD
Sep 21, 2023 · Backend Development

Cut Java 21 Record Pattern Matching Code in Half

This article demonstrates how Java 21's switch pattern matching and record deconstruction let you replace verbose instanceof checks with concise two‑line snippets, even for nested records, dramatically simplifying code that extracts fields from complex objects.

Java 21Pattern MatchingRecord Patterns
0 likes · 4 min read
Cut Java 21 Record Pattern Matching Code in Half
21CTO
21CTO
Sep 20, 2023 · Backend Development

What’s New in Java 21? Explore 15 JEPs, Preview Features, and Performance Boosts

Java 21, the latest long‑term support release, brings 15 JEPs—including string templates, record patterns, virtual threads, and a foreign function API—along with extensive performance, security, and maintenance updates, while extending Java 11 support through 2032.

JEPJava 21Virtual Threads
0 likes · 12 min read
What’s New in Java 21? Explore 15 JEPs, Preview Features, and Performance Boosts
Programmer DD
Programmer DD
Sep 3, 2023 · Fundamentals

Master Java 21 Template Expressions for Clean String Interpolation

This article introduces Java 21's new Template Expressions, explains how STR and FMT processors enable safe, efficient string interpolation and formatting—including multi‑line strings, arithmetic, method calls, and object fields—while providing practical code examples and best‑practice guidance.

Java 21String InterpolationString Templates
0 likes · 8 min read
Master Java 21 Template Expressions for Clean String Interpolation