Java's Project Valhalla Updates
· 2 min read
One line of code just rewrote the rules of performance.
The Problem We’ve Lived With Since 1995:
// TODAY (Java 21+)
class User {
private final Optional<Integer> userId; // 😩 Wrapper bloat
}
Java forces a brutal choice:
- Primitives (int, double)
- fast . stored directly, no overhead
- Not objects
List <int>illegal,Optional<int>compiler error
- Wrappers (Integer, Double)
- Works in generics, collections, APIs
- 4× memory, boxing/unboxing, GC thrashing, cache misses
Tradeoff = Pain. Every Java dev has paid the tax.
##Enter Project Valhalla (JDK 23+ Preview)
// TOMORROW
class User {
private final Optional<int> userId; // ✅ Primitive speed + Object API
}
Valhalla delivers Value Classes + Primitive Objects:
- Acts like an object (nullable, generic-ready)
- Runs like a primitive (stack-allocated, zero boxing)
Why This Changes Everything
- Billions of heap objects vanish → lower latency, happier GC
- Collections become truly efficient →
ArrayList<int>= raw array speed - Cleaner APIs → no more int... vs Integer... overload wars
- Legacy migration is trivial → swap Integer → int in generics
Abstraction should cost nothing. – Project Valhalla
Try It Today (JDK 23 Early Access)
jshell --enable-preview
val point = record Point(int x, int y) {}
List<Point> points = List.of(new Point(1,2), new Point(3,4));
System.out.println(points);
// → [Point[x=1, y=2], Point[x=3, y=4]]
No heap allocation. Pure stacks.
TL;DR: Valhalla = Object flexibility + Primitive performance.
Java just got fast again.