virtual threads diagram

banking teller analogy

• A teller 👨 is like a platform thread 🧵 because they can only process one customer 👱 at a time.
• A customer 👱 is like a task ✅ that the thread needs to perform.
• Sometimes, a customer 👱 or a task may need some external information or resources 💾 before it can be completed. This is called a blocking operation 🛑 because it blocks the teller 👨 [or the platform thread 🧵] from doing anything else until it is resolved.
• The teller 👨 [or the platform thread 🧵] can park the customer 👱 or the task that is blocked, and move on to the next one in line. This means that the customer 👱 or the task is temporarily suspended ⏸️, and will resume ▶️ when the blocking operation is resolved. This is called a parked virtual thread because it is a virtual thread that is parked by the platform thread 🧵.
• By parking the customer 👱 or the task, the teller 👨 [or the platform thread 🧵] can process more customers or tasks at the same time, and increase the concurrency. Concurrency is the ability to run multiple tasks at the same time or in parallel.