Episode 49 “LazyConstants in JDK 26” [IJN]
Posted on March 6, 2026
Lazily initializing fields in Java is error-prone and undermines constant-folding. JDK 26 comes with JEP 526, which previews LazyConstant, a type that lazily initializes a value through a given Supplier. It executes that supplier at most once successfully and then assigns the value to a field annotated with @Stable, which allows constant folding. This API is also a poster child for how OpenJDK develops and evolves features.
Links:
- JDK 26
- JEP 526
- JEP Draft for Lazy Constants in JDK 27
- Inside Java Newscast #101 on reflective final field mutation
- Inside Java Podcast #37 with Per Minborg - Efficient Initialization Using Stable Values
- Inside Java Podcast #42 with John Rose - From Sumatra to Panama, from Babylon to Valhalla
Make sure to also check the Duke’s Corner podcast on dev.java.
Additional resources
- Inside.java : News and views from members of the Java team at Oracle
- Dev.java : The Destination for Java Developers
- OpenJDK
- Oracle Java
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