Azul Zulu
By Azul Systems
Azul Zulu is a certified, open-source distribution of OpenJDK built and supported by Azul Systems, a company specializing in Java runtime technology. It is available in both a free community edition and commercially supported editions, and…
Definition
Azul Zulu is a certified, open-source distribution of OpenJDK built and supported by Azul Systems, a company specializing in Java runtime technology. It is available in both a free community edition and commercially supported editions, and it targets a particularly broad range of operating systems, CPU architectures, and older Java versions compared to many other OpenJDK distributions, with commercial support available for organizations that need it.
Overview
Azul Zulu was built by Azul Systems, a company whose entire business is centered on Java virtual machine technology, to offer organizations a certified OpenJDK build with the option of enterprise-grade commercial support behind it, something a purely community-run distribution cannot always guarantee. Azul has long positioned itself as a specialist in Java runtime performance and support, and Zulu is the vehicle through which that expertise reaches organizations that want an OpenJDK build backed by a company whose core competency is exactly this technology. Like other OpenJDK distributions, Zulu compiles the same upstream OpenJDK source into binaries, but Azul distinguishes its offering through TCK certification for Java SE compliance, an unusually wide platform matrix that includes less common combinations of operating system and CPU architecture, and extended support windows for older Java versions that have reached end-of-life upstream but that Azul continues to patch under its commercial editions. Within the OpenJDK distribution landscape, Zulu competes directly with Eclipse Temurin, Amazon Corretto, and BellSoft Liberica, all built from the same source code; Zulu differentiates itself primarily through the depth of its commercial support tier, called Zulu Enterprise, and through Azul's additional, separate product line of alternative JVM implementations such as Azul Prime, which is a distinct, more heavily engineered runtime rather than a standard OpenJDK build. In practice, Zulu's free community edition is used the same way any other free OpenJDK distribution is used, as a general-purpose Java runtime for development and production, while its paid enterprise tier is chosen by organizations that specifically need extended support for legacy Java versions, guaranteed patch SLAs, or support for niche hardware platforms not well covered by other distributions. The practical decision point for teams evaluating Zulu against alternatives like Temurin or Corretto usually comes down to specific support requirements: organizations running very old, unsupported-elsewhere Java versions, or deploying to unusual hardware, often find Zulu's broader platform matrix and legacy support commitments a better fit, while teams with standard, current infrastructure needs may find little practical difference between Zulu's free edition and other vendor-neutral OpenJDK builds. Procurement is also a factor for larger organizations: having a single named vendor accountable for a support contract, rather than a community project or a cloud provider's incidental offering, can simplify internal vendor-risk review even when the underlying binary behaves identically to a competing distribution. This distinction matters most for regulated industries and large enterprises with formal vendor-management processes, where a documented support agreement is often a prerequisite for approving a piece of infrastructure regardless of its technical merits.
Key Features
- Built and supported by Azul Systems, a dedicated JVM technology vendor
- Available in both a free community edition and paid enterprise tiers
- Certified against the Java SE Technology Compatibility Kit
- Covers an unusually broad range of operating systems and CPU architectures
- Offers extended support for older, upstream-unsupported Java versions
- Provides commercial support SLAs under the Zulu Enterprise offering
- Built from the same upstream OpenJDK source code as other distributions
- Complements Azul's separate high-performance Prime JVM product line