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Azul Core

The world’s best supported builds of OpenJDK.

Formerly Zulu Enterprise / Embedded

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70% less expensive
(typical savings vs. Oracle)

Azul Core is designed for the enterprise, with the certified builds, tight security, and cost efficiencies you need to run today’s business–critical, Java-based services.

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More Trust

Chosen by leading global brands, Azul Core offers engineering support and 100% open-source builds that are Java SE compliant and TCK verified, with 100% success migrating off Oracle Java.

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More Value

Azul Core is a one-to-one replacement for Oracle Java SE with the most architectures, package types, and configurations options compared to other OpenJDK providers.

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Azul Core delivers quarterly Critical Patch Updates for rapid deployment into production, backed by an industry-leading support SLA.

Industry Use Cases:

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Higher Education 

Azul provides a drop-in replacement for any Java application across every department at a fraction of the price of Oracle Java and no threat of audit.

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Energy & Utilities 

Azul’s future-proof solution eliminates Oracle Java licensing exposure while ensuring compliance with industry regulations and government legislation.S

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Electronics

Azul’s embedded solution is ideal for self-contained systems that require security and stability at an affordable price point.

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Software & Technology

Azul’s OEM option provides software vendors with a standards-based, secure and supported JVM from a trusted vendor.

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Manufacturing

Fully-integrated builds of Azul Core Fully supported, open-source Java development and runtime platform that is ensure manufacturing systems are secure and continuously up-to-date.

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IoT & Embedded

Azul provides IP protection for application code backed by long-term, industry-leading support. 

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Secure, stable, protected, up-to-date.

Azul is the only Java leader besides Oracle that delivers stabilized security builds, builds that enterprises traditionally prefer to use. Deploy updates with confidence, keeping your Java applications secure, stable and regression-free.

Azul also delivers full updates that combine bug fixes, new features, and security patches.

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Support for Java 6 & 7

Legacy Production Support for Java versions that are end of life by OpenJDK and Oracle including Java 6 & 7, as well as deprecated technologies like Java Applets and Java Web Start (JWS).*​ 

* Only for those customers who have purchased Legacy Production Support.

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Verified TCK standards compliant.

Azul Core is verified compliant with Java SE, so your new and existing applications can run without modifications.​

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Accelerate Oracle Java Migration

JVM Inventory, a feature of Azul Intelligence Cloud, catalogs running JVMs to accelerate classification, streamline migration and simplify tracking of Oracle Java instances, slashing months off OpenJDK migration timelines and helping to ensure ongoing Oracle Java licensing compliance and audit defense.​

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Guard your IP.

Azul indemnifies Azul Core subscribers and protects their software from copyleft contamination.

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Faster Startup and Warmup.

The Azul Zulu JVM distributed with Azul Core leverages startup optimization technologies such as Coordinated Restore at Checkpoint (CRaC)* to provide instant start at optimal speed for Java applications.

*CRaC is available for Java 17 and 21 on Linux

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The best Java runtimes for OEMs & ISVs.

Azul Core support plans offer redistribution-ready downloadable runtimes, access to all security updates, technical troubleshooting, and a wide set of packaging alternatives. Azul sales will work with you to determine the bundle requirements, support, and pricing model needed to match your requirements.

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See Core in Action

University of Southern Queensland: seamlessly migrated thousands of applications in weeks, avoiding an Oracle Java renewal that would have increased license costs by 60%.

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“Switching from Oracle JRE to Azul was as easy as it can get. It’s basically a drop-in replacement.”

Alexander Mueller, CTO

“We found it very easy to do business with Azul. Azul’s business model and terms were very flexible, and they helped to simplify our operations by removing constraints.”

Michihiro Okada, General Manager of Software R&D Division

“Azul provides a well-supported, reliable and secure Java JDK and runtime that we use in many of SAS Institute’s products and solutions. The satisfaction of thousands of SAS customers demonstrates the quality of the Azul Platform.”

Sam Penfield, Product Manager

“Azul was a drop-in replacement and migration has taken less than three months. Had we known how seamlessly and smooth the process would be, we would have switched from Oracle Java to Azul Java much earlier on.”

Michael Thalhammer, Head of Software Development

“By adopting Azul Core and teaming with Azul, we ensure that our customers always have access to secure, certified, and tested builds of Java.”

Carl Gould, Co-director of Software Engineering

Support Tiers

We offer two levels of enterprise technical support subscriptions to accommodate your business, and application requirements. All backed by our highly trained customer support engineers with extensive knowledge of the JVM, memory management, Java performance issues, and usage of production application visibility tools.

Standard
Premium
Quarterly Releases
Included
Plus: Out-of-cycle bug fixes & early release access
Support hours and first response SLA
Business hours, next business day
24x7x365, one hour first response
Channels
Limited tickets & phone/email/web support
Unlimited tickets & phone/email/web support
SLA for Quarterly CPU
Max 15 days (target same day as Oracle)
Max 48 hours (target same day as Oracle)

Your Guide to Java Migration

See why “OpenJDK Migration for Dummies” may be your smartest move. Move to the OpenJDK distribution that’s right for you with help from a new Wiley Guide sponsored by Azul.

Download the Digital Version
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Demo: Azul Core

Watch this short demo on-demand to see a high-level visualization of Azul Core in action.

Watch On-Demand

Discover Even More

A Java Discovery Tool to Improve Migrations
Data Sheets

JVM Inventory Datasheet

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Research & White Papers

OpenJDK Migration for Dummies

 Azul Platform Core Datasheet
Data Sheets

Azul Platform Core Datasheet

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Webinars & Videos

Life After Oracle Java
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The best Java support in the industry.
Bar none.

There’s a reason Azul has a 100% customer satisfaction rating:
our relentless focus on helping customers unleash the true power of Java.

Product releases that meet or exceed Oracle

Long Term Support (LTS) based on 8+2 year product lifecycle model.

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Expert problem resolution available 24/7

Includes stabilized security updates, root cause analysis, performance analysis and tuning. Experienced engineers on call worldwide 24x7x365. 

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Fast, straightforward Java migration

Our drop-in solution and advisory services make it easy to migrate
from the Oracle JDK.

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Core Components

Azul Mission Control

Analyze and profile your systems during development and production.

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Azul Commercial Compatibility Kit

The Azul Commercial Compatibility Kit (ZCCK) is designed to ensure compatibility of Azul Zulu Builds of OpenJDK (Azul’s 100% open source, certified builds of OpenJDK) and Oracle’s proprietary Java SE 6-8.

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ZIUpdater

Apply time zone definition updates to deployed JDKs.

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Migration Toolkit

Analyze and profile your systems during development and production.

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IcedTea-Web

IcedTea-Web is an open source implementation of Java Web Start.

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jHiccup

jHiccup is an open source tool designed to measure the pauses and stalls (or “hiccups”) associated with an application’s underlying Java runtime platform.

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jRT Socket Response Tool

Accurately track end-user response time in live apps.

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Azul Inspector

Get insight into the system and app settings that affect performance.

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Garbage Collection Log Analyzer

Garbage Collection Log Analyzer (GCLA) is a tool to view and interpret Java heap, pause time, and operating system metrics gathered while running the Azul Zulu Builds of OpenJDK.

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Ready? So are we.

Our Java experts are ready to answer your questions and show you how much you could save by switching to Azul.

*Based on Oracle Java SE subscription pricing for server deployments

Azul Core FAQs

Is Java open source?

Yes. Java’s core platform — OpenJDK — is fully open source under the GNU General Public License v2 with Classpath Exception (GPLv2+CE). Oracle also publishes its own Oracle JDK builds, which include proprietary components and require a paid subscription for commercial use. 

Azul Core delivers 100% open-source, TCK-verified builds of OpenJDK (Azul Zulu) with enterprise-grade support — the freedom and transparency of open source backed by production-ready SLAs, security updates, and dedicated Java engineers. 

Is OpenJDK open source?

Yes. OpenJDK is the official reference implementation of Java SE and is fully open source under GPLv2+CE. Anyone can download, use, and distribute it without paying licensing fees.

Azul Core is built on 100% open-source OpenJDK and passes the Java SE Technology Compatibility Kit (TCK), guaranteeing your applications run without modification. Azul adds commercial support, quarterly Critical Patch Updates, and an 8+2 year LTS lifecycle on top of the open-source foundation.

 

Is Oracle Java open source?

Partially. Oracle contributes heavily to the open-source OpenJDK project, but Oracle JDK — the builds Oracle distributes — includes proprietary components and has required a paid commercial license since 2019. Running Oracle JDK in production without a subscription puts organizations at risk of audit and compliance penalties.

Azul Core is a certified, drop-in replacement for Oracle Java SE with no proprietary strings attached. Switching eliminates Oracle licensing exposure, with typical savings of 70% or more — and Azul’s advisory services make migration fast and risk-free.

 

Is Java open source free for commercial use? 

OpenJDK is free for commercial use under GPLv2+CE. Oracle JDK is not — Oracle’s 2019 license change made it a paid product for production environments, creating significant licensing liability for organizations that didn’t switch.

Azul Core provides fully supported OpenJDK builds with no commercial licensing fees. You get the security updates, SLAs, and expert support that production workloads demand, at up to 70% lower cost than Oracle Java.

 

Can I use OpenJDK for commercial use?

Yes — OpenJDK can be used commercially, free of charge. The GPLv2+CE license is specifically designed to allow OpenJDK to be used as a runtime for any application, including commercial ones, without triggering copyleft obligations on your own code.

Azul Core builds on this freedom by adding IP indemnification, protecting subscribers from copyleft contamination claims. You get commercially safe OpenJDK with full legal and technical backing.

 

How do I install OpenJDK?

OpenJDK can be installed via package managers (apt, brew, dnf/yum, winget), Docker images, or direct downloads from distribution providers. The specific steps depend on your OS and OpenJDK provider.

Azul Zulu — the OpenJDK distribution included with Azul Core — offers the broadest coverage of any provider: every LTS and current release, across Linux, macOS, and Windows, for x64, ARM, Alpine, and more. Install via package manager, container image, or direct download at azul.com/downloads.

 

Does OpenJDK require a license? 

No. OpenJDK is released under GPLv2+CE and does not require a commercial license. Oracle JDK does require a paid subscription for production use — a common source of confusion since both are often referred to simply as “Java.”

Azul Core provides OpenJDK builds with zero licensing fees, plus commercial support, quarterly security patches, and legal indemnification — all the benefits of a commercial Java product without the Oracle overhead.

 

How long will OpenJDK be supported?

Support timelines vary by provider and Java version. The OpenJDK community maintains each LTS release (Java 8, 11, 17, 21) for several years, but after community EOL, organizations on unpaid builds are on their own for security fixes.

Azul Core follows an 8+2 year LTS lifecycle — well beyond most providers. For organizations still on Java 6 or 7, Azul also offers Legacy Production Support for versions long past OpenJDK and Oracle EOL, ensuring continuity without a forced migration.