Evidence label: deterministic synthetic teaching model. This browser page executes a small JavaScript model of the stated policy. It does not run Java, access a JVM, create actual worker threads or contact a tool. Use it to understand the boundary and compare assumptions before running the separate Java example.
Predict the boundary before running the model
With two workers and service time four, predict whether three arrivals per tick can be sustained. Run with queue capacity four, then compare the unbounded queue without changing service capacity.
Write a prediction for the terminal outcome, then use Run model. The summary reports the calculated end-state for the current inputs. The trace begins at its first event so you can inspect how that outcome is reached. Next event advances one row; Show complete trace exposes every row. Restart trace changes only the viewing position, not the selected inputs.
Run and inspect the synthetic experiment
Expected outcomes and useful counterexamples
The bounded queue never exceeds its configured capacity and excess arrivals are rejected. The unbounded model keeps accepting while backlog grows. Accepted work equals completed plus running plus queued work at the observation boundary.
Change one input, rerun and compare the exact values in the table. A boundary that still holds under the changed inputs is more informative than an attractive animation. Trace rows and text labels carry the result; the visual colors are supplementary. The model recalculates only after Run model, so an edited input does not silently replace the trace you are inspecting.
What this lab cannot establish
The model has a fixed number of workers, FIFO order and exact service times. It omits thread creation, task deadlines, retries, caller-runs execution and queue-node overhead. A real ThreadPoolExecutor with different core and maximum sizes follows additional admission rules.
The controls have intentionally small finite ranges. They are not operational recommendations. No output here demonstrates production capacity, a recommended heap size, successful cancellation of a remote effect or a GC performance improvement. Use the downloadable Java fixture and then a representative integration test to investigate those separate questions. Keep the runtime version and the measurement method with any real results.
Continue with the Java implementation
Keep Bounded Java Executor Queues From Hiding Harness Overload contains the original Java fixture, the failure analysis and its primary references. Continue with Publish Stable Java Harness Checkpoints Without Sharing Mutable State to examine the next ownership boundary. The examples have synthetic non-personal inputs and do not require an account, API key or external service.
All six guides and labs · Lab catalog.
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