[6.2.x] Fix TextMessage body thread safety (#2188)#2204
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This fixes the rare null body issues seen on the broker when using text messages by using synchronization when marshaling or unmarshaling the body into a String to prevent a race condition from causing the body to end up null. This has been optimized to use volatiles and double checked locking to avoid synchronization unless needed. (cherry picked from commit b131c3d)
Validates the fix for the race between getText(), storeContentAndClear() and copy() on a shared ActiveMQTextMessage instance that could null the message body: getText() decoded content into text and cleared content while storeContentAndClear() observed the pre-clear content, skipped re-encoding, and cleared text — losing the body permanently. Triggered on the broker by XPath selector evaluation or JMX browse racing dispatch marshalling, with the network bridge copy() adding a third participant. Four tests: - sequential control: getText/storeContentAndClear round trips preserve the body - two-way race: 20k iterations of concurrent getText vs storeContentAndClear; no iteration may lose the body - three-way race including copy(): both the original and the copy must retain a recoverable body (pre-fix this loses the original's body within a few thousand iterations) - deterministic lock-discipline pin: the fix serializes the text/content state transitions on the message instance, so storeContentAndClear() must block while another thread holds the message monitor; fails immediately on any regression to unsynchronized transitions Verified failing (2 of 4) against the pre-fix base and passing on this branch. Co-authored-by: Matt Pavlovich <mattrpav@apache.org> (cherry picked from commit e1368d5)
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This fixes the rare null body issues seen on the broker when using text messages by using synchronization when marshaling or unmarshaling the body into a String to prevent a race condition from causing the body to end up null. This has been optimized to use volatiles and double checked locking to avoid synchronization unless needed.
(cherry picked from commit b131c3d)