Oracle Java Alternatives: OpenJDK Comparison Guide 2026

Why Organisations Are Leaving Oracle Java

Oracle's January 2023 licensing change replaced the per-named-user and per-processor metric for Java SE with a single employee-based subscription: the Java SE Universal Subscription. Every employee in your organisation — regardless of whether they ever touch Java — counts towards the licence requirement. At list prices of $15 per employee per month for smaller tiers, a 5,000-person company pays $900,000 per year just for the right to run any Oracle Java.

For organisations that previously licensed Java on a per-processor basis or relied on the free Oracle Binary Code Licence (BCL) for Java 8, the shock is severe. Many have experienced effective cost increases of 800% or more. The response from the market has been decisive: 81% of organisations are migrating all or part of their Oracle Java estate to free, open-source OpenJDK distributions.

What makes this migration unusually straightforward is that Oracle JDK and OpenJDK are, technically, the same product. Since Java 11, Oracle has aligned both codebases. The "Oracle JDK" is simply Oracle's build of OpenJDK with some cosmetic branding. You can replace an Oracle Java binary with an OpenJDK binary from any reputable distribution and your application will not know the difference.

Understanding the OpenJDK Ecosystem

OpenJDK is the open-source reference implementation of the Java Platform, Standard Edition. It is governed by the OpenJDK project under the auspices of Oracle and a broad community of contributors. The OpenJDK source code is freely available, and dozens of vendors produce their own builds — called OpenJDK distributions — which they test, certify, and optionally support commercially.

The four distributions that dominate enterprise adoption are Amazon Corretto, Azul Zulu, Eclipse Temurin (formerly AdoptOpenJDK), and Red Hat OpenJDK. All four pass the Java Technology Compatibility Kit (TCK) — the official conformance test — and are considered production-grade replacements for Oracle Java.

Choosing between them is largely a function of your cloud provider relationship, your existing vendor ecosystem, your support requirements, and the Java versions you need to maintain. Here is what you need to know about each.

Amazon Corretto

Amazon Corretto is Amazon Web Services' no-cost, production-ready OpenJDK distribution. Amazon uses Corretto internally across its entire global infrastructure, giving it a level of real-world validation that few distributions can match. Corretto is TCK-certified, available for Linux, Windows, and macOS, and includes Amazon-originated patches that are contributed upstream but may arrive in Corretto before they appear in the upstream OpenJDK release.

Support Timelines

Corretto is notable for its extended Long-Term Support (LTS) commitments. Amazon provides free security updates for Corretto Java 8 until at least 2030 and Corretto Java 11 until at least 2032. These timelines frequently exceed Oracle's own LTS commitments for the equivalent releases, which makes Corretto particularly attractive for organisations running Java 8 or Java 11 workloads that are not yet ready to upgrade.

Best For

Organisations that run their Java workloads on AWS — either on EC2, ECS, Lambda, or managed services — will find Corretto the path of least friction. Commercial support for Corretto is available but limited to AWS environments. If you are not on AWS, commercial support options are narrower than with Azul or Red Hat.

Azul Zulu (Azul Platform Core)

Azul Systems is a pure-play Java company whose entire commercial model is built around the Java ecosystem. Azul Zulu Builds of OpenJDK are free, production-ready, TCK-certified distributions available for an exceptionally wide range of hardware and operating system combinations — including legacy platforms that other distributions have dropped. Azul also provides builds optimised for ARM architectures, stripped-down JREs for containerised deployments, and distributions that include OpenJFX for graphical applications.

Commercial Support

Azul Platform Core — the commercially supported version of Azul Zulu — includes stabilised, security-tested builds with a rapid patch release cycle and access to Azul's engineering team for issue resolution. This makes Azul the leading choice for organisations that want the zero-cost OpenJDK model for the bulk of their estate but need a contractual support SLA for mission-critical workloads.

Best For

Organisations with diverse or complex Java estates — including those requiring support for older versions, unusual hardware platforms, or legacy operating systems — will benefit most from Azul's breadth of coverage. Azul is also the preferred migration target for many large financial services and healthcare organisations that need commercial support independence from any single cloud provider.

Eclipse Temurin (Eclipse Adoptium)

Eclipse Temurin is the continuation of the widely-used AdoptOpenJDK project, now managed under the Eclipse Foundation as part of the Adoptium Working Group. Its sponsors include Google, IBM, Microsoft, Azul, Red Hat, and other major technology companies — making it one of the most broadly-endorsed OpenJDK distributions available. Temurin is TCK-verified, freely downloadable, and available for all major platforms.

Community and Governance

The multi-vendor governance model of the Adoptium project means Temurin is subject to less single-vendor influence than Corretto (Amazon) or Red Hat OpenJDK. For procurement teams concerned about vendor lock-in, this broad-based governance structure is an important consideration. The distribution is community-maintained in terms of build infrastructure, but the backing of its Working Group members provides a high level of confidence in its longevity.

Commercial Support

Temurin itself does not come with direct commercial support from the Eclipse Foundation, but several Adoptium Working Group members — including Azul and Red Hat — offer commercial support for Temurin-based deployments. Production usage at 22.1% market share in 2024 makes it the single most widely deployed OpenJDK distribution by volume.

Best For

Organisations that want a vendor-neutral, community-driven OpenJDK distribution with maximum governance transparency. Also ideal for development, test, and CI/CD pipeline environments where a free, widely-tested binary is the priority.

Red Hat OpenJDK

The Red Hat build of OpenJDK is the Java runtime bundled with Red Hat Enterprise Linux (RHEL) and provided as a free download for Windows. Red Hat OpenJDK is deeply integrated with the RHEL lifecycle, and for organisations with active RHEL subscriptions, it effectively arrives as part of their existing platform support contract.

Integration with RHEL

If your Java workloads run on RHEL — whether on-premises, on AWS, on Azure, or on Google Cloud — you already have access to Red Hat OpenJDK as part of your RHEL entitlement. This can significantly simplify the licence and support argument: you are not adding a new vendor relationship, you are using a runtime that your platform vendor already covers.

Best For

Organisations with a predominantly RHEL Linux estate and an active Red Hat subscription. Also relevant for organisations already in the IBM ecosystem, as IBM's JDK support is closely aligned with Red Hat OpenJDK through their shared ownership structure.

Side-by-Side Comparison

The table below summarises the key decision factors across the four leading distributions and Oracle Java SE:

• Licence Cost: Oracle Java SE Universal Subscription starts at $15/employee/month. All four OpenJDK alternatives are available at zero licence cost. Commercial support for the alternatives typically runs from $50 to $300 per server per year — a fraction of Oracle's employee-based pricing.
• TCK Certification: All four alternatives are TCK-certified, meaning they conform to the Java SE specification. Application compatibility is not a concern.
• Java 8 / 11 LTS Support: Amazon Corretto provides the longest free LTS coverage for Java 8 and 11. Azul, Red Hat, and Eclipse Temurin (via commercial partners) all offer extended support. Oracle's free OpenJDK builds only cover the current and previous LTS release.
• Commercial Support Availability: Azul and Red Hat offer the most mature commercial support programmes. Corretto commercial support is limited to AWS environments. Temurin commercial support is available through third-party partners.
• Platform Coverage: Azul Zulu leads on platform breadth, including legacy OS and hardware coverage. Corretto leads for AWS-native deployments. Red Hat OpenJDK leads for RHEL-centric estates.
• Audit Risk: Switching to any OpenJDK alternative eliminates Oracle Java SE audit exposure entirely. Oracle has no contractual basis to audit usage of non-Oracle JDK distributions.

How to Choose the Right Alternative

The right OpenJDK alternative is almost always determined by your infrastructure and support requirements rather than technical differences. The following decision logic applies to most enterprises:

If your workloads run primarily on AWS, start with Amazon Corretto. It is pre-tested in the environment where you will run it, Amazon's internal dogfooding provides additional validation, and the LTS timelines are among the most generous available. The limitation is commercial support outside AWS — plan accordingly for any on-premises or multi-cloud workloads.

If you need commercial support independent of any cloud provider — particularly for financial services, healthcare, or regulated environments — Azul Platform Core is the leading choice. Azul's sole commercial focus is Java, and its engineering support capability is correspondingly deep.

If you run a RHEL-dominant Linux estate, Red Hat OpenJDK is effectively already licensed and the path of least procurement friction. Your Java runtime becomes part of your platform contract.

If you prioritise vendor-neutral governance or need the widest possible community validation, Eclipse Temurin is the most widely deployed OpenJDK distribution and has the broadest multi-vendor endorsement. Pair it with an Azul or Red Hat commercial support contract if you need contractual SLAs.

Migration Approach

The technical steps to migrate from Oracle Java SE to an OpenJDK alternative are straightforward, but the organisational preparation matters as much as the technical execution. A four-phase approach minimises risk.

Phase 1: Inventory

You cannot migrate what you cannot find. Run a comprehensive discovery of all Oracle Java installations across your estate — including production, development, test, disaster recovery, and embedded environments. Capture the Java version, the deployment type (JDK vs JRE), the operating system, and the application using each installation. This inventory also defines your Oracle Java licence exposure going forward.

Phase 2: Distribution Selection

Select your target distribution or distributions using the criteria above. Most organisations adopt a primary distribution and designate a secondary for edge cases. Document the selection rationale for governance purposes — this will be relevant if Oracle audits your estate and challenges the removal of their software.

Phase 3: Testing and Remediation

The binary swap between Oracle JDK and an OpenJDK alternative is technically simple, but your test coverage should still validate the swap. Test the target application with the replacement JDK in a staging environment before rolling to production. Pay particular attention to any Oracle-specific commercial features — such as Oracle Advanced Management Console or Oracle Flight Recorder in pre-Java 11 versions — that may need a functional equivalent.

Phase 4: Removal and Documentation

Uninstall Oracle Java from all systems where it has been replaced. Document the removal date for each deployment. Retain the evidence of removal — Oracle has used download records as the basis for retroactive audit claims, and being able to demonstrate that you uninstalled Oracle Java on a specific date and replaced it with a named OpenJDK distribution is your primary defence.

What This Means for Your Oracle Support Costs

Migrating away from Oracle Java SE eliminates the Universal Subscription cost entirely. There are no Oracle support fees for OpenJDK alternatives — support is either free (community) or contracted directly with your chosen distribution vendor at market rates that are consistently lower than Oracle's subscription pricing.

Organisations with significant Oracle Database or Oracle Fusion Middleware deployments should note that Java SE licensing is separate from database support. Migrating the JDK used by Oracle's own products may be constrained by Oracle's certification requirements — consult your Oracle contracts before replacing JDKs within Oracle-certified software stacks.

Oracle's annual support fee increases of 8% per year apply to any remaining Oracle software support contracts. Eliminating the Java SE subscription removes one of the fastest-growing cost lines from your Oracle estate and reduces the baseline on which future 8% annual increases would compound.

Common Questions

Is it legal to use OpenJDK distributions commercially?

Yes. OpenJDK distributions are released under the GNU General Public License version 2 with Classpath Exception (GPLv2+CE), which explicitly permits commercial use. There is no Oracle licence required to run Amazon Corretto, Azul Zulu, Eclipse Temurin, or Red Hat OpenJDK in a commercial production environment.

Can Oracle audit my use of OpenJDK?

Oracle has no contractual basis to audit your use of OpenJDK distributions that are not theirs. Oracle's audit rights under the Oracle Technology Network Licence Agreement (OTN) and the Java SE subscription terms apply only to Oracle's own products. If you have completely removed Oracle Java and replaced it with a third-party OpenJDK distribution, Oracle cannot audit that deployment. However, you should retain evidence of the removal in case Oracle challenges whether Oracle Java was still present at the time of a claimed compliance shortfall.

What about Java 8 — is it still supported?

Oracle Java 8 public updates ended for commercial use in March 2019 without a paid subscription. Amazon Corretto provides free security updates for Java 8 until at least 2030. Azul provides extended support for Java 8 as part of its commercial support offering. There is no technical reason to remain on Oracle Java SE for Java 8 deployments when free alternatives with longer support timelines exist.

Will Oracle claim I owe them money for past usage?

Oracle may issue retroactive audit claims based on download records for past Oracle Java usage. This risk exists regardless of whether you have migrated. The best defence is to have completed your migration, uninstalled Oracle Java, and retained documentation that your current estate runs only OpenJDK distributions. Engage an independent Oracle Java licensing specialist if you receive any retroactive claim — initial Oracle audit demands are rarely the final settlement figure.

Conclusion

The decision to move from Oracle Java SE to an OpenJDK alternative is one of the clearest cost-reduction opportunities available to enterprise IT organisations in 2026. The technical case is unambiguous: Oracle JDK and the leading OpenJDK distributions are functionally identical. The commercial case is equally clear: zero licence cost versus potentially hundreds of thousands of dollars per year under the employee-based Universal Subscription model.

The main variables are which distribution to choose and how to execute the migration at scale. Both are solvable with the right inventory data, a structured migration plan, and — where Oracle audit exposure is involved — independent licensing advisory support to manage the risk of retroactive claims.

Redress Compliance provides independent Oracle Java licensing assessments, migration planning, and audit defence support. We work exclusively on the buyer side and have no commercial relationship with Oracle or any JDK vendor.