Scoped Values
Scoped Values, finalised in Java 24 (JEP 487), provide a mechanism to share immutable data within and across threads in a structured, predictable way — designed as a safer and more scalable alternative to ThreadLocal in the era of virtual threads.
A ScopedValue binds a value for the duration of a delimited scope (a lambda or method call). Any code executing within that scope — including code in child threads spawned via structured concurrency — can read the value. When the scope exits, the binding is automatically removed.
static final ScopedValue<User> CURRENT_USER = ScopedValue.newInstance();
ScopedValue.where(CURRENT_USER, authenticatedUser)
.run(() -> {
// Any code here, including virtual threads, can read CURRENT_USER.get()
processRequest();
});The key advantages over ThreadLocal:
- Immutable — a scoped value cannot be mutated after binding, eliminating a class of hidden-state bugs.
- Structured lifetime — the binding is automatically removed when the scope exits, with no risk of thread pool leakage.
- Virtual-thread friendly — with millions of virtual threads, per-thread mutable state is expensive; immutable scoped values are shared cheaply.
Scoped Values are designed to work in conjunction with Structured Concurrency and Virtual Threads.
See Also
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