Java's Project Valhalla Finally Lands in JDK 28 — What It Means for Developers (opens in new tab)

After more than a decade of development, Project Valhalla is finally entering the JDK mainline. JEP 401 (Value Classes and Objects) will be integrated into OpenJDK targeting JDK 28 (March 2027) as a preview feature. This is not a small update. The pull request adds 197,000+ lines of code across 1,816 changed files. Oracle's Lois Foltan described it as an "extremely large change" — and that might be an understatement. Here's what's changing, why it matters, and what it means for everyday Java ...