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Zulu Embedded FAQ

Basic Facts

What is Azul Zulu Embedded?

Zulu Embedded is Azul Systems’ branding of builds of OpenJDK for ISVs, embedded OEMs, and IoT developers and product teams. Zulu Embedded builds of OpenJDK are certified compliant with the Java SE standard for JDK6, JDK7, JDK8, and future releases of OpenJDK that are designated for long-term support. Commercial builds of Zulu Embedded are also guaranteed to protect customer IP from the risk of open source license contamination. 

What are the processor architectures supported by Zulu Embedded?

Processor Family32 bit64 bit

Which operating systems are supported by Zulu Embedded?

Supported operating systems include Linux, Windows, macOS, QNX, and Solaris. 

  • Windows Client 10, 10 IoT Core, 8.1, 8, 7 and Server 2016, 2012R2, 2012, 2008 R2
  • All major Linux distros, including RHEL, CentOS, Ubuntu, SLES, Debian, Oracle Linux, Amazon Linux, Container Linux by CoreOS, Alpine Linux, Wind River Linux and Automotive Grade Linux.
  • QNX
  • macOS Sierra and High Sierra (for Java 9, 8 and 7)
  • Solaris11 and 12 (for Java 8 and 7)

Contact your Azul representative for information regarding specific distros and versions. 

What is a “certified” build of OpenJDK?

Zulu is verified compliant with the Java Standard Edition (“Java SE”) specifications using the OpenJDK Community Technology Compatibility Kit (TCK) licensed from Oracle. The TCK is a suite of more than 120,000 tests which ensures that a binary build of OpenJDK meets all the speculations of the individual JSRs for a given version of Java SE (e.g. Java 8). Azul is just 1 of a small handful of organizations and companies that licenses the TCKs for Java 8, 7, and 6, and the only vendor that licenses all current OpenJDK versions (10, 9, 8, 7, and 6) today. In addition to running the TCKs on all Zulu builds, the Zulu QA team also tests the binaries with other Java application stacks (e.g. Tomcat, Red Hat JBoss, etc.) and across different operating systems.

How is Zulu Embedded licensed?

GPL v2 with Classpath Exception. Zulu is licensed under GPLv2 with Classpath Exception which allows vendors to redistribute Zulu with their own Java products without “contaminating” it or being forced to license their own code under GPLv2. In addition to rights conferred via GPLv2 + CPE, Zulu binaries are fully TCK-tested, and are certified as compatible and compliant implementations of their related Java SE specifications and associated umbrella JSRs, providing additional patent protections that are available only to compliant implementations through the JCP’s JSR licensing mechanisms.

What Zulu OpenJDK packages and Java versions are available?

What are Zulu Embedded Community Builds?

Azul makes certain Zulu Embedded versions of the full JDK freely accessible from the Zulu Embedded Download page.  Availability of these releases may vary over time and for a given Java version. For companies and partners that require support for these releases and access to the latest Azul fixes, Azul offers Zulu Enterprise and Zulu Embedded support packages, including 24×7 mission-critical support. Azul also offers customized or “embedded” bundles of Zulu (e.g. headless JRE, Compact Profiles, specific CPU types, etc.) which are not available on the Zulu Community site, but are available via subscription.

What does Zulu Embedded support consist of?

Azul offers a number of enterprise support packages for the certified Zulu build images, including 24×7 mission-critical support offerings. The Zulu product is supported by a dedicated team of engineers and QA professionals that provide tier 1, 2 & 3 support, including root cause analysis, temporary patches, and backporting bug fixes and security patches. Support is available both for current releases and older versions (e.g. Java 7, 6), including extended support beyond Oracle end-of-public-updates.

What is Zulu Embedded?

Zulu Embedded is a 100% open source, fully “certified” and “verified” build of OpenJDK that can be customized for your specific embedded needs (i.e. for a specific device, appliance or software package). Zulu Embedded offers wider CPU support, including x64, x86, Arm v7, Arm v8, and PowerPC target types. It is ideal for companies shipping embedded systems or software bundles on multiple Java versions (Java SE 6 and later). ISVs/IHVs can specify the target operating system, underlying hardware architecture, bitness (32- or 64-bit) as well as Zulu’s overall footprint, ranging from full Java development environments to ultra-compact, runtime-only configurations. Azul only offers Zulu Embedded binaries as part of our Enterprise / Embedded support packages and are not available from the Zulu Community site.

What Zulu Embedded options are available?

Zulu Embedded offers full Java development environments to ultra-compact, runtime-only configurations. You can fully customize the Zulu Embedded packaging configuration, including processor type, Java version (Java 6, 7 or 8), bitness (32- vs 64-bit), OS support, bundle attributes (e.g. JRE-headless, compact 3, 2, and 1 profiles), and specific OpenJDK patch update level as well as build packaging (e.g. ZIP).

Does Azul offer mission-critical support for Zulu and Zulu Enterprise?

Azul has a proven track record supporting mission-critical applications within large organizations, including low latency trading applications in global banks and financial exchanges (e.g. LMAX, Voya, Wells Fargo, Barclays), eCommerce applications (e.g. MasterCard, Saks Fifth Avenue, Starbuck, Viking Lines), revenue-critical web sites (e.g. eBay, Priceline.com), and SaaS/IaaS deployments (Microsoft, Workday). Azul also provides mission-critical support to large partners, including Microsoft Azure, Payara, and many embedded device manufacturers.

What is your product release velocity across your different Zulu Enterprise / Embedded support offerings?

Zulu follows OpenJDK’s quarterly scheduled updates (i.e. OpenJDK critical patch updates or “CPUs”), and responds to any midcycle critical security update released by Oracle, Red Hat, or ourselves. Azul reviews the Common Vulnerabilities and Exposures (“CVE”) list to identify which code modules got patched, whether those lie within or outside Zulu, and, with our release notices, provide a summary of change impact. Azul also backports all changes into older version of Java (i.e. Java 7 and 6). Due to the sensitive nature of security details, Azul only publishes the CVE details in the Zulu Enterprise release notes PDF editions and provides these directly to subscribers. Zulu public user documentation does not enumerate any CVE details.

Does Azul upstream bug fixes?

Azul Zulu is not a fork of OpenJDK and Azul’s OpenJDK committers upstream all changes and bug fixes back to the OpenJDK community. However, upstreaming changes can take as much as 6 months for Oracle’s approval and it find their way back into the OpenJDK code. Therefore, it is possible that at any given time, a Zulu Enterprise or Embedded release could contain a bug fix, temporary patch or code change made by Azul that Oracle has not yet released back into the OpenJDK sources.

Technical Facts

 Can I use Zulu Embedded with Eclipse?

Yes, Zulu Embedded is a fully Java SE compliant JVM and can be used with any development tool that supports Java SE. 



OpenJDK project is the open source project where new Java versions are created and older versions maintained.

Java SE is the standard (specification, reference implementation, and test suite) that an implementation must pass to be certified as Java compliant.


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