• 17 February 2026 In Android 17, apps targeting SDK 37 or higher will receive a new implementation of MessageQueue where the implementation is lock-free. • The new implementation improves performance and reduces missed frames, but may break clients that reflect on MessageQueue private fields and methods. • To learn more about the behavior change and how you can mitigate impact, check out the MessageQueue behavior change documentation. • This technical blog post provides an overview of the MessageQueue rearchitecture and how you can analyze lock contention issues using Perfetto. • The Looper drives the UI thread of every Android application. • It pulls work from a MessageQueue, dispatches it to a Handler, and repeats.

Article Summaries:

  • Android 17 replaces the legacy, lock‑based MessageQueue with a lock‑free “DeliQueue” for apps targeting SDK 37+. The change removes the single monitor lock that previously caused contention and priority inversion, improving UI thread throughput and cutting missed frames. Developers may need to adjust if their code reflects on MessageQueue’s private fields, as the new implementation may break such assumptions. The update is documented in the MessageQueue behavior change guide and a technical blog explains the new algorithms and how to use Perfetto to diagnose lock‑contention issues. The goal is smoother main‑thread performance across Android devices.

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