Synchronized blocks in MethodOverrides are hurting concurrency

[kennymacleod]

Affects: 5.1.x, 4.3.x

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The fix for issue #18905 introduced synchronized blocks into the MethodOverrides class to fix a race condition. While this fixed the original bug, the introduction of the synchronized blocks is really hurting the concurrency of our application. We make use of method injection in a hot spot in our application, which has very high request concurrency. All of those requests go through MethodOverrides, and through these synchronized blocks. While the individual operations are fairly quick, it's still significant enough to cause serious concurrency degradation.

Can this class be reworked to avoid synchronized blocks?

[smarquard]

It would be nice to backport this to 4.3.x as well. We saw this show up in a Sakai 20 (using spring-beans 4.3) thread dump with multiple request threads blocked because of this issue.