Revisit CGLIB AOP proxy warnings for final methods [SPR-15436]

[spring-projects-issues]

Juergen Hoeller opened SPR-15436 and commented

The change triggered by #16241 led to a downgrade of the log category for non-interceptible final methods from WARN to INFO, aligned with the then-new log messages for non-interceptible package-visible methods. However, public final methods which happen to implement methods in a service interface remain a serious problem for CGLIB proxy generation: We should either log those specific messages on WARN again or reject such target classes upfront.

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Issue Links:

• Clarification: Spring AOP pointcuts match protected methods when CGLIB is used [SPR-15354] #19917 Clarification: Spring AOP pointcuts match protected methods when CGLIB is used
• CglibAopProxy needs to detect package-visible methods when defined in a different ClassLoader [SPR-11618] #16241 CglibAopProxy needs to detect package-visible methods when defined in a different ClassLoader

Referenced from: commits 665e6cf, 43e806c, 9b2f9e6, 0d0b879

[spring-projects-issues]

Juergen Hoeller commented

CglibAopProxy logs an explicit warning for an interface-implementing method marked as final now, covering the particular case where interception would work with an interface-based proxy but does not work with a target-class proxy. This happens at WARN level now, whereas the regular messages about final methods (potentially never invoked through the proxy) keep happening at INFO level.