Java's Project Valhalla Finally Lands in JDK 28 — What It Means for Developers

Short summary

Project Valhalla, after 10+ years of development, arrives in OpenJDK 28 (March 2027) as a preview feature introducing value objects that optimize memory and speed by flattening values inline rather than using heap pointers. This breaks existing code relying on synchronization and represents a fundamental redesign of Java's 30-year-old object model. Early migration starts with auditing synchronized code and rethinking which classes need identity versus pure value semantics.

• •Project Valhalla entering JDK 28 as preview (March 2027) after 10+ years of development
• •Value objects optimize memory and iteration speed by eliminating pointer dereferencing
• •Breaking change: code synchronizing on boxed primitives will throw exceptions

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