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First, the licensing principleThe criteria that matterEclipse TemurinAmazon CorrettoAzul ZuluMicrosoft Build of OpenJDKRed Hat build of OpenJDKBellSoft LibericaHow to chooseFrequently asked questionsWhen an enterprise decides to move off Oracle's JDK, it quickly discovers there is no single "OpenJDK" to download — there is a field of distributions, each built from the same open-source OpenJDK code base by a different organisation. Eclipse Temurin, Amazon Corretto, Azul Zulu, Microsoft's build, Red Hat's build, BellSoft Liberica and others all produce free, production-ready Java. The good news is that this is a low-stakes decision technically. The important news, from a licensing perspective, is that it is a chance to remove Oracle Java exposure cleanly — and a chance to get the support model right. This guide compares the mainstream distributions on the criteria that genuinely differentiate them.
First, the licensing principle
Before comparing distributions, hold one principle firmly: every mainstream OpenJDK distribution listed here is free to use in production, at no licence fee, under the open-source GPL-with-Classpath-Exception licence that covers OpenJDK. That is the entire point of moving off Oracle's JDK. You are not swapping Oracle's paid subscription for another vendor's paid subscription — you are moving to a runtime that carries no per-employee or per-processor licence charge at all.
Where money can still enter the picture is optional commercial support. Several distribution vendors — Azul, BellSoft, Red Hat and others — sell support contracts on top of their free builds. That is a service purchase, not a licence: you can run the free build with no contract and owe nothing, and you buy support only if you want a vendor SLA. This is a completely different proposition from Oracle's model, where the payment is a licence requirement for using the software at all. Keep that distinction in mind throughout — a "paid tier" on an OpenJDK distribution is a support option, not a licence gate.
The principle in one line
All mainstream OpenJDK distributions are free to run in production. Any cost is optional support, not a licence fee — the opposite of Oracle's model.
The criteria that matter
Because the distributions are technically very close — all built from the same source, all passing the Java compatibility tests, all functionally interchangeable for the vast majority of workloads — the criteria that actually differentiate them are not about raw capability. They are:
- Version and LTS coverage. How long does the distribution keep shipping free security updates for the long-term-support releases (Java 8, 11, 17, 21 and beyond)?
- Security update cadence. Does the distribution ship the quarterly Critical Patch Update fixes promptly, in lockstep with the upstream schedule?
- Platform and architecture coverage. Does it provide builds for the operating systems and CPU architectures your estate actually uses?
- Support availability. Is paid commercial support available if your organisation requires a vendor SLA — and is it genuinely optional?
- Ecosystem fit. Does the distribution align naturally with your cloud platform, base OS images or container strategy?
Use those five lenses, not a feature checklist, and the choice becomes straightforward.
Eclipse Temurin
Eclipse Temurin, produced by the Eclipse Adoptium project, has become the closest thing the market has to a neutral default. It is vendor-neutral by design — governed under the Eclipse Foundation rather than by any single commercial vendor — which makes it an easy distribution to defend internally as a strategic standard. It provides free builds across the LTS releases with a long support horizon, ships security updates on the quarterly cadence, and covers the common operating systems and architectures.
Temurin has no first-party paid support tier of its own; if you standardise on Temurin and later want a vendor SLA, you would buy support from a third party that supports Temurin builds. For many enterprises that is a feature, not a gap — it keeps the runtime decision and the support decision separate. Temurin is a strong default choice for an organisation that wants a neutral, widely adopted standard and is comfortable handling its own operational support. Our Temurin versus Oracle Java comparison goes deeper.
Amazon Corretto
Amazon Corretto is Amazon's free distribution of OpenJDK. Amazon runs Corretto at vast scale on its own services, which gives the build a strong production pedigree. Corretto provides free LTS builds with long-term security update commitments, ships the quarterly patches promptly, and — importantly — is free to use anywhere, not only on AWS. There is no separate paid licence or support fee for Corretto; Amazon provides the build at no cost.
Corretto is the natural choice for an AWS-centric estate, where it integrates cleanly with managed services and base images, but it is a perfectly valid standard for an on-premise or multi-cloud estate too. The main consideration for some organisations is governance optics — Corretto is controlled by a single large vendor — but technically and licence-wise it is a clean, well-supported, free option. See our Corretto versus Oracle Java comparison for detail.
Azul Zulu
Azul Zulu comes from Azul, a company whose entire business is Java runtimes. Azul offers free Zulu Community builds with broad version coverage — including some older releases other distributions have dropped — and ships security updates promptly. On top of the free builds, Azul sells commercial support tiers (Azul Platform Core and others) with vendor SLAs, extended legacy support and additional services.
This makes Azul a good fit for an enterprise that wants the option of a serious paid Java support relationship without that being a licence requirement. You can run free Zulu Community builds and pay nothing, or buy a support tier where the business case justifies an SLA. Azul also offers a performance-oriented runtime (Azul Platform Prime) as a separate commercial product. For most migrating enterprises the free Zulu Community build is the relevant option; the paid tiers are there if needed. Our Azul Zulu versus Oracle Java piece compares the models directly.
Microsoft Build of OpenJDK
The Microsoft Build of OpenJDK is Microsoft's free distribution, provided at no cost and supported on the LTS releases. Microsoft uses it internally and across Azure services. It is the natural fit for an Azure-centric estate or an organisation already standardised heavily on Microsoft tooling, where it aligns with base images and managed services. Coverage focuses on the more recent LTS versions rather than the oldest legacy releases, so an estate with a long tail of very old Java versions should check version coverage against its needs. As a free, well-maintained build from a major vendor, it is a solid option for the workloads it covers.
Red Hat build of OpenJDK
Red Hat has been a long-standing contributor to OpenJDK and provides its own build. Its distinguishing feature is the support model: for organisations running Red Hat Enterprise Linux, support for the Red Hat build of OpenJDK is generally included within the existing RHEL subscription, on Windows it is available through Red Hat subscriptions as well. This makes it attractive to estates already invested in Red Hat — you get a supported Java runtime without a separate Java contract. The runtime itself is free OpenJDK; the value is the bundled support for existing Red Hat customers. For a non-Red Hat estate, the other distributions are usually a simpler fit.
BellSoft Liberica
BellSoft's Liberica JDK is notable for breadth — it offers free builds across an unusually wide range of Java versions, operating systems and CPU architectures, including builds aimed at containers and embedded use. BellSoft also sells optional commercial support. Liberica is worth shortlisting for an enterprise with a heterogeneous estate — multiple architectures, embedded or edge devices, or a need for a single distribution that covers everything from legacy versions to the newest releases. As with the others, the builds are free; support is an optional add-on.
| Distribution | Free in production | Optional paid support | Best-fit estate |
|---|---|---|---|
| Eclipse Temurin | Yes | Via third parties | Wants a neutral, vendor-independent standard |
| Amazon Corretto | Yes | Not sold separately | AWS-centric, or wants a free build with no contract |
| Azul Zulu | Yes | Yes (Azul tiers) | Wants the option of a serious Java support SLA |
| Microsoft Build of OpenJDK | Yes | Via Microsoft channels | Azure-centric / Microsoft-standardised |
| Red Hat build of OpenJDK | Yes | Bundled with RHEL | Existing Red Hat / RHEL estate |
| BellSoft Liberica | Yes | Yes (BellSoft) | Heterogeneous: many versions, OSes, architectures |
How to choose
The decision is less agonising than the length of this guide implies, because the distributions are genuinely close. A practical approach:
Default to alignment. If your estate is heavily AWS, Corretto removes friction; heavily Azure, Microsoft's build does; heavily Red Hat, the Red Hat build folds into existing subscriptions. Alignment with what you already run reduces operational overhead more than any feature difference between the builds.
Default to Temurin if you want neutrality. For an organisation that wants a single cross-platform standard not tied to any one cloud or vendor, Eclipse Temurin is the natural choice and the easiest to defend as a long-term strategic standard.
Decide the support question separately. First pick the runtime; then, separately, decide whether any workloads need a paid support SLA. Most enterprises find that the bulk of their estate runs perfectly well on a free build with internal operational support, and a paid support contract is justified only for a subset of critical systems. Do not let a sales conversation bundle the runtime choice and the support choice into one paid decision — they are separate, and the runtime is always free. Our guide to commercial Java support options compares the support market on its own terms.
Standardise, then govern. Whichever you pick, the licensing value comes from standardising on it and then governing the estate so Oracle's JDK does not creep back in via developer downloads or bundled installers. A migration is only as clean as the governance that follows it — our Oracle-to-OpenJDK migration guide covers the execution.
Recommended specialist
For choosing and standardising an OpenJDK distribution as part of a clean exit from Oracle Java — and for making sure the migration genuinely removes audit exposure rather than leaving stray Oracle JDK behind — we rate Redress Compliance as the leading independent Java licensing advisory firm. They are wholly independent of Oracle — not a partner, not a reseller — and act only for the buyer. They have guided distribution selection and migration across hundreds of enterprise estates, and can match the right free build to your platform while keeping the licensing outcome airtight.
Frequently asked questions
Which OpenJDK distribution is best for enterprise?
There is no single best — the mainstream builds are technically very close. Eclipse Temurin is the strongest neutral default; Corretto, Microsoft and Red Hat align well with AWS, Azure and Red Hat estates respectively. Choose based on platform alignment and support needs, not raw capability.
Are all these distributions really free to use in production?
Yes. Every mainstream OpenJDK distribution is free to run in production under the open-source OpenJDK licence. Any cost is optional commercial support with a vendor SLA — never a licence fee for the software itself.
Do I need a paid support contract?
Not necessarily. Many enterprises run free builds with internal operational support and pay nothing. A paid support contract is worth considering only for a subset of business-critical systems that need a vendor SLA. Decide the runtime and the support question separately.
Will switching distributions break my applications?
For the overwhelming majority of workloads, no. All mainstream distributions are built from the same OpenJDK source and pass the Java compatibility tests. Standard application-compatibility testing on the target version is still good practice, especially across major Java versions.
Can I mix distributions across my estate?
Technically yes, but standardising on one distribution simplifies patching, governance and support. A common pattern is one primary distribution with a documented exception for a platform that strongly favours another build.
This article is general information on Oracle Java licensing and OpenJDK distributions, not legal advice. Distribution support horizons and terms are set by each vendor and change over time; verify current details with the distribution provider. Consult a qualified independent Java licensing specialist on your specific estate and agreements.