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 but still allows constant-folding.

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JDK 26 introduces JEP 526, which previews LazyConstant — a new Java type that lazily initializes a value via a Supplier, executes that supplier at most once successfully, and stores the result in a @Stable-annotated field to enable constant folding. This addresses the error-prone nature of manual lazy initialization patterns in Java while preserving JIT optimization opportunities. The episode also touches on how OpenJDK iteratively develops and evolves features, with a draft JEP already targeting JDK 27.

Episode 49 “LazyConstants in JDK 26” [IJN] – Inside.java