Eclipse Temurin is the successor to AdoptOpenJDK: it is the same project, rebranded and re-governed under the Eclipse Foundation as Eclipse Adoptium. AdoptOpenJDK officially migrated to Eclipse Adoptium in August 2021, and the HotSpot-based JDK builds that were previously called AdoptOpenJDK are now published as Eclipse Temurin. If you are still using AdoptOpenJDK, you should migrate to Temurin, as AdoptOpenJDK is no longer maintained and receives no security updates.
The migration from AdoptOpenJDK to Eclipse Temurin is the recommended path for existing users. The builds are functionally equivalent, the governance model is similar (community-driven with corporate backing), and the migration process is straightforward. For teams evaluating their JDK strategy at the same time, Azul Zulu is a compelling alternative with broader Java version and platform coverage.
What Is AdoptOpenJDK?
AdoptOpenJDK was a community-driven project started in 2017 to provide free, open-source, pre-built OpenJDK binaries. Before AdoptOpenJDK, obtaining free production-ready Java binaries required building from source or relying on Oracle’s commercial offering. AdoptOpenJDK filled this gap by providing tested, packaged JDK builds for multiple platforms and Java versions.
AdoptOpenJDK offered two JVM variants: HotSpot builds (the standard JVM from OpenJDK) and OpenJ9 builds (IBM’s alternative JVM). In August 2021, AdoptOpenJDK formally transitioned to the Eclipse Foundation as Eclipse Adoptium. The HotSpot builds became Eclipse Temurin. The OpenJ9 builds moved to IBM, rebranding as IBM Semeru Runtime. AdoptOpenJDK infrastructure and repositories are no longer actively maintained, and no new security patches are being published there.
What Is Eclipse Temurin?
Eclipse Temurin is the official continuation of AdoptOpenJDK’s HotSpot builds. It is produced by the Eclipse Adoptium working group under the Eclipse Foundation, with corporate governance members including IBM, Microsoft, Red Hat, Alibaba, and others. Temurin provides LTS releases for Java 8, 11, 17, 21, and 25, all TCK (Technology Compatibility Kit) certified and packaged for x64 and ARM64 Linux, Windows, and macOS.
For teams migrating from AdoptOpenJDK (HotSpot variant), Eclipse Temurin is the direct and recommended migration target. The binaries are built from the same OpenJDK source code, use the same HotSpot JVM, and are governed by the same community model. If you were using AdoptOpenJDK OpenJ9 builds, the equivalent migration target is IBM Semeru Runtime.
Eclipse Temurin vs AdoptOpenJDK Comparison
| Feature | Eclipse Temurin | AdoptOpenJDK |
|---|---|---|
| License | GPLv2 + Classpath Exception | GPLv2 + Classpath Exception |
| Cost | Free (active) | Free (DEPRECATED) |
| Support | Community (Adoptium) | None (end-of-life) |
| LTS Versions | 8, 11, 17, 21 | 8, 11 (no updates) |
| Performance | HotSpot JVM | HotSpot JVM (frozen) |
| Platforms | x64/ARM Linux, Windows, macOS | Multiple (no updates) |
| TCK Certified | Yes | Was certified (stale) |
Why AdoptOpenJDK Is Deprecated
AdoptOpenJDK is deprecated because the project formally migrated to the Eclipse Foundation in 2021. The AdoptOpenJDK repositories, download infrastructure, and issue trackers are no longer actively maintained. Security vulnerabilities discovered after the migration are not being patched in AdoptOpenJDK builds. Any organization still running AdoptOpenJDK in production is running an unpatched JDK and should migrate immediately.
The migration to Eclipse Adoptium was a deliberate, planned transition with community consensus. The Eclipse Foundation’s governance model provides stronger long-term sustainability assurances than the informal AdoptOpenJDK structure. Temurin benefits from formal working group governance, corporate member financial support, and the Eclipse Foundation’s established open-source infrastructure.
Migrating from AdoptOpenJDK to Eclipse Temurin or Azul Zulu
If you are using AdoptOpenJDK HotSpot builds, migration to Eclipse Temurin is a drop-in replacement. Download the equivalent Temurin build (same Java version, same platform) from adoptium.net, replace your JDK installation, and restart your application. No code changes are required.
Migration to Azul Zulu is equally straightforward and offers additional benefits. Zulu is built from the same HotSpot OpenJDK sources and is binary-compatible with Temurin for the same Java version. Migration to Zulu provides access to a wider Java version range (6 through 25+), Alpine Linux builds, and the option to add Azul Core commercial support. Download Zulu builds from azul.com/downloads.
If you were using AdoptOpenJDK OpenJ9 builds (now IBM Semeru Runtime), migration requires more consideration. OpenJ9 and HotSpot have different JVM behaviors including different garbage collection defaults, different JIT compiler behavior, and potentially different startup and memory characteristics. Test your application against the target JVM before migrating in production.
Which Should You Choose?
If you were using AdoptOpenJDK, migrate immediately to either Eclipse Temurin or Azul Zulu. Both are maintained, receive security patches, and are TCK-certified. Staying on AdoptOpenJDK is not a safe option.
Choose Eclipse Temurin if you want the most direct migration path with the same community governance model that AdoptOpenJDK had. Temurin is vendor-neutral and well-supported for Java 8, 11, 17, and 21 on standard platforms.
Choose Azul Zulu if you need broader platform support (Alpine Linux) a wider Java version range (6 through 25+) or want the option to add commercial support through Azul Core without changing distributions. Zulu provides a richer long-term foundation than Temurin for organizations that may have evolving infrastructure requirements.
Frequently Asked Questions
Is Eclipse Temurin the same as AdoptOpenJDK?
Eclipse Temurin is the direct successor to AdoptOpenJDK’s HotSpot JDK builds. It is the same codebase and same community, rebranded and re-governed under the Eclipse Foundation as of August 2021. For HotSpot users, Temurin is functionally equivalent to the AdoptOpenJDK builds it replaced.
Should I migrate from AdoptOpenJDK to Temurin?
Yes, immediately. AdoptOpenJDK is no longer maintained and receives no security patches. Running AdoptOpenJDK in production means running a JDK with known, unpatched CVEs. Migrate to Eclipse Temurin or Azul Zulu as soon as possible. The migration is a straightforward JDK replacement requiring no code changes.
What happened to AdoptOpenJDK OpenJ9?
The OpenJ9-based AdoptOpenJDK builds were taken over by IBM and rebranded as IBM Semeru Runtime. If you were using AdoptOpenJDK with the OpenJ9 JVM, your migration target is IBM Semeru Runtime, not Eclipse Temurin. Be aware that OpenJ9 and HotSpot have behavioral differences that require testing before production migration.
Where can I download AdoptOpenJDK?
AdoptOpenJDK binaries still exist at adoptopenjdk.net but should not be used for production. They are not receiving security updates. Download Eclipse Temurin from adoptium.net or Azul Zulu from azul.com/downloads as maintained, actively patched replacements.
Is Azul Zulu a drop-in replacement for AdoptOpenJDK?
Yes, for HotSpot-based AdoptOpenJDK builds. Azul Zulu uses the same HotSpot JVM from the same OpenJDK source code, making it fully compatible with applications that ran on AdoptOpenJDK. The migration is a JDK path update, not a code change. Zulu adds broader version and platform coverage plus an optional commercial support tier.
Conclusion
Eclipse Temurin is AdoptOpenJDK: it is the same project, continued under better governance and a more sustainable foundation. If you are still running AdoptOpenJDK, migration to Temurin or Azul Zulu is urgent, not optional. AdoptOpenJDK is unpatched software with known security vulnerabilities.
For the broadest JDK coverage, widest platform support, and the option to add commercial SLA support, Azul Zulu is the recommended migration target. It is free, TCK-certified, actively maintained, and provides broad flexibility as your needs evolve.