عدم القابلية للتغيير والحصر

في هذا الدرس

avoid locking by design.

الموضوعات المخطط لها

• Immutable objects (final fields, no setters, records) are safe to share freely.
• Replace state by swapping a reference to a new immutable snapshot.
• Thread confinement: data used by only one thread needs no lock (local variables, ThreadLocal).
• Spring singletons are shared by all requests; keep them stateless or hold only thread-safe state.
• Copy defensively when passing mutable data across threads.