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IBM Semeru Runtime Open Edition vs Azul Zulu: catalog facts
IBM Semeru Runtime Open Edition	Azul Zulu
Best for: Java developers wanting an OpenJ9-based OpenJDK build	Best for: Developers who need a specific Java version installed on any desktop OS
Free Free to download, with optional paid enterprise support from IBM.	Free The Zulu builds of OpenJDK are free to download from Azul.
macOS, Command line	Windows, macOS, Linux, Command line
Uses the Eclipse OpenJ9 JVM instead of HotSpot Drop-in replacement for other OpenJDK builds All 3 strengths for IBM Semeru Runtime Open Edition Uses the Eclipse OpenJ9 JVM instead of HotSpot Drop-in replacement for other OpenJDK builds Free binaries with optional commercial support	Builds for every current long-term Java version, back to Java 8 Packages for Windows, macOS and Linux from one page All 3 strengths for Azul Zulu Builds for every current long-term Java version, back to Java 8 Packages for Windows, macOS and Linux from one page Based directly on OpenJDK
Only useful to people running or developing Java software OpenJ9 tuning options differ from HotSpot	A runtime and toolkit, with no graphical tools of its own Many vendors ship near-identical OpenJDK builds, so the choice is often about support
Downloadable app	Downloadable app
Open source	Open source
License not stated	License: GPL-2.0 with Classpath Exception
No account needed	Not stated if an account is needed
Offline features available	Offline features available
Official website Full listing and sources Sources for IBM Semeru Runtime Open Edition developer.ibm.com/languages/semeru-runtimes Catalog checked October 1, 2026	Official website Full listing and sources Sources for Azul Zulu azul.com/downloads Catalog checked October 2, 2026

“Not stated” means we have not confirmed it. Features can vary by device and plan.