All OpenJDK Versions

All OpenJDK Versions

• OpenJDK 6: The first open-source Java release, launched in 2007.
• OpenJDK 7: Introduced simplified syntax and Fork/Join framework.
• OpenJDK 8: Added lambda expressions and Stream API.
• OpenJDK 11: LTS release with HTTP/2 and Java Flight Recorder.
• OpenJDK 17: Latest LTS with sealed classes and improved security.

All OpenJDK Versions

OpenJDK (Open Java Development Kit) is the reference implementation of the Java Platform, Standard Edition (Java SE). Over the years, OpenJDK has released numerous versions, each bringing significant enhancements, new features, and optimizations to the Java ecosystem.

This article explores all major OpenJDK versions in detail, highlighting their key features, improvements, and the impact they’ve had on Java development across industries.

OpenJDK 6

Release Year: 2007
Overview: The first official release of OpenJDK, based on Java SE 6, began Java’s open-source journey. It focused on substantial performance improvements, better usability, and enhanced developer productivity.

Key Features:

• Support for scripting languages through the javax.script API.
• JDBC 4.0 enhancements, enabling seamless database connectivity.
• Desktop improvements, including splash screen support and enhanced drag-and-drop functionality.
• Early steps toward modularization for a more flexible development process.

Read what a long-term release for Java is.

OpenJDK 7

Release Year: 2011
Overview: OpenJDK 7 introduced groundbreaking features that solidified Java’s position as a versatile and forward-thinking programming language. This release marked a major shift in Java’s evolution with innovations aimed at developers and system architects.

Key Features:

• Project Coin: Simplified language constructs such as try-with-resources, improved type inference, and better exception handling.
• Fork/Join Framework: Enhanced parallelism capabilities for modern multicore processors.
• NIO.2: An upgraded file system API, enabling more efficient file manipulation.
• Support for dynamic languages via the invoke dynamic bytecode, fostering language interoperability.

OpenJDK 8

Release Year: 2014
Overview: OpenJDK 8 is one of the most transformative releases, widely adopted for its introduction of functional programming features and significant advancements in stream processing. It continues to be a favorite among developers.

Key Features:

• Lambda expressions and the Stream API enable functional programming paradigms in Java.
• A comprehensive Date and Time API (java.time) for robust and intuitive date-time manipulation.
• Nashorn JavaScript Engine is used to integrate JavaScript code directly within Java applications.
• Compact Profiles: A feature for building smaller Java applications optimized for resource-constrained environments.
• Enhanced annotations, paving the way for cleaner and more manageable code.

OpenJDK 9

Release Year: 2017
Overview: OpenJDK 9 introduced modularization, a revolutionary change in how Java applications are structured, deployed, and executed. It laid the foundation for modern application architectures.

Key Features:

• Project Jigsaw: Introduced a modular system to break the JDK into modules, improving scalability and security.
• jshell: An interactive Java shell for experimenting and prototyping Java code.
• Ahead-of-Time Compilation (AOT): Enhanced runtime performance through precompiled bytecode.
• Streamlined and enhanced garbage collection for more efficient memory management.

OpenJDK 10

Release Year: 2018
Overview: As the first release in Java’s six-month release cycle, OpenJDK 10 focused on incremental developer productivity improvements and better memory management techniques.

Key Features:

• Local variable type inference using the var keyword simplifies code without compromising readability.
• Experimental container awareness for running Java applications in containerized environments.
• Improved application class-data sharing (AppCDS), reducing startup times and memory usage.

OpenJDK 11 (LTS)

Release Year: 2018
Overview: As a Long-Term Support (LTS) release, OpenJDK 11 became the cornerstone for enterprise applications, offering stability, modern features, and extended support options.

Key Features:

• HTTP/2 Client API for asynchronous communication and improved web interactions.
• Simplified file handling with new APIs, making file operations more intuitive.
• Java Flight Recorder (JFR) for in-depth monitoring and diagnostics.
• Remove deprecated features like Java EE and CORBA modules, streamlining the JDK.
• Support for Unicode 10, enhancing text processing capabilities.

OpenJDK 12

Release Year: 2019
Overview: OpenJDK 12 delivered enhancements to improve developer productivity and runtime efficiency. It also refined some preview features introduced earlier.

Key Features:

• Preview of switch expressions, enabling concise and flexible coding patterns.
• Shenandoah GC: A low-pause garbage collector optimized for large heaps.
• JVM Constants API: Improved runtime behavior through better handling of constants.

OpenJDK 13

Release Year: 2019
Overview: Focused on incremental improvements, OpenJDK 13 enhanced text handling and application startup performance.

Key Features:

• Text Blocks (preview): Simplified multiline string literals for cleaner and more readable code.
• Dynamic CDS Archives: Improved application startup by dynamically archiving class data.
• ZGC enhancements for better performance in low-latency environments.

OpenJDK 14

Release Year: 2020
Overview: OpenJDK 14 introduced pattern-matching capabilities and improved runtime feedback mechanisms, emphasizing developer productivity.

Key Features:

• Pattern matching for instanceof (preview), simplifying type-checking logic.
• Records (preview): A new class type for modeling immutable data objects.
• Improved NullPointerException messages, providing better-debugging insights.
• JFR Event Streaming for real-time monitoring and analytics.

OpenJDK 15

Release Year: 2020
Overview: This release focused on enhancing type safety and garbage collection efficiency while introducing sealed classes.

Key Features:

• Sealed classes (preview) for defining restricted class hierarchies.
• Improvements to the Z Garbage Collector (ZGC) for more efficient memory management.
• Hidden classes for frameworks, allowing the creation of classes not accessible via reflection.

OpenJDK 16

Release Year: 2021
Overview: OpenJDK 16 continued refining Java for modern use cases, focusing on better performance and incremental API enhancements.

Key Features:

• Vector API (incubator): Improved performance for vector computations.
• Migration to Git for source control, streamlining version management.
• Unix-domain socket support for enhanced interprocess communication (IPC).
• Enhanced preview of records and pattern matching.

OpenJDK 17 (LTS)

Release Year: 2021
Overview: Another Long-Term Support (LTS) release, OpenJDK 17, balanced innovation with stability, introducing advanced and deprecating outdated features.

Key Features:

• Finalized sealed classes for controlled extensibility.
• Pattern matching for switch (preview), improving code readability.
• Remove RMI activation and other deprecated APIs for a leaner JDK.
• Context-specific deserialization filters to enhance security.

OpenJDK 18

Release Year: 2022
Overview: OpenJDK 18 introduced features to simplify development workflows and expand default support.

Key Features:

• UTF-8 as the default character set, improving text handling globally.
• Simple Web Server API (incubator) for lightweight web-serving tasks.
• JavaDoc improvements with code snippets for enhanced documentation.

OpenJDK 19

Release Year: 2022
Overview: OpenJDK 19 emphasized new concurrency tools and language features, catering to modern development needs.

Key Features:

• Virtual threads (preview) from Project Loom for simplified concurrency.
• Structured concurrency (incubator), streamlining multithreaded programming.
• Further refinements to pattern matching for switch (third preview).

OpenJDK 20

Release Year: 2023
Overview: OpenJDK 20 built upon recent advancements, focusing on concurrency and memory optimizations for high-performance applications.

Key Features:

• Extended previews of virtual threads and structured concurrency.
• Memory segment API enhancements, improving efficiency in memory management.

FAQs

What is OpenJDK?
OpenJDK is the open-source implementation of Java SE, serving as its reference standard.

Which version of OpenJDK was the first?
OpenJDK 6, released in 2007, was the first open-source version.

What is the significance of OpenJDK 8?
OpenJDK 8 introduced lambda expressions, the Stream API, and a modern Date-Time API and became a widely used version.

What is an LTS release in OpenJDK?
LTS (Long-Term Support) versions like OpenJDK 11 and 17 offer extended support for enterprise use.

How does OpenJDK 9 stand out?
It introduced modularization through Project Jigsaw, transforming Java’s structure and scalability.

What makes OpenJDK 11 important?
As an LTS release, it includes HTTP/2 support, Java Flight Recorder, and improved file handling.

Why are non-LTS versions released?
Non-LTS versions, like OpenJDK 12, deliver innovative features for experimentation before adoption in LTS releases.

What features did OpenJDK 17 bring?
Sealed classes, enhanced cryptography, and pattern matching for switch statements.

What is OpenJDK 20’s focus?
It expands on virtual threads and structured concurrency for modern application needs.

How often are OpenJDK versions released?
A new OpenJDK version is released every six months, with LTS versions every three years.

Why is OpenJDK 6 still mentioned?
As the first version, it laid the foundation for Java’s open-source journey and modern iterations.

What are the benefits of modularization in OpenJDK 9?
It reduces memory overhead, improves security, and simplifies application deployment.

Can OpenJDK 8 be used for enterprise applications?
It remains a reliable choice due to its stability and comprehensive feature set.

What is the role of OpenJDK 15?
It introduced sealed classes (preview) and ZGC improvements for better memory management.

Where can I download OpenJDK versions?
Official OpenJDK versions can be downloaded from OpenJDK’s website or vendor-specific distributions like Red Hat OpenJDK and Amazon Corretto.