Improve TreeTypeAdapter thread-safety #1976
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Gson claims to be thread-safe so TreeTypeAdapter.delegate() might be called by multiple threads. To guarantee that each thread sees a fully constructed `delegate`, the field has to be `volatile`.
gson/src/main/java/com/google/gson/internal/bind/TreeTypeAdapter.java
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Nov 21, 2021
* Improve TreeTypeAdapter thread-safety Gson claims to be thread-safe so TreeTypeAdapter.delegate() might be called by multiple threads. To guarantee that each thread sees a fully constructed `delegate`, the field has to be `volatile`. * Improve TreeTypeAdapter thread race comment
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Gson claims to be thread-safe so
TreeTypeAdapter.delegate()might be called by multiple threads. To guarantee that each thread sees a fully constructeddelegate, the field has to bevolatile.Otherwise when a user-defined type adapter with non-
finalfields (even though it is stateless) is being used as delegate a thread might see an incomplete constructed instance. See Safe Publication and Safe Initialization in Java; the current case ofTreeTypeAdapter.delegate()would be similar to the "Unsafe Local DCL & Unsafe Singleton" case shown in that blog post.