volatile happens-before — safe publication of objects?

volatile and publication

volatile ensures visibility and ordering (happens-before) for reads/writes. It does not compose atomic read-modify-write—use atomics for counters.

• Safe publication of immutable object reference after construction.
• Double-checked locking requires volatile instance field.
• Not a substitute for synchronizing compound invariants.
• JMM guarantees readers see latest written value.

private volatile boolean shutdown;

void shutdown() { shutdown = true; }

boolean isShutdown() { return shutdown; }