REPLACING ANNOTATED PROGRAM CODE IN A NETWORKED COMPUTING ENVIRONMENT

An approach for replacing one program code library (or method(s) thereof) with another program code library (or method(s) thereof) during execution is provided. Specifically, an annotation (e.g., comprising a runtime optimization request and associated performance/measurement criteria) within a program code file will be detected, analyzed, and used to monitor/assess the performance of a running set of methods of the program code file or the like (e.g., a set of initial/original methods). As this is occurring, a set of substitute methods will be identified from a program code library (e.g., based on similarities to the original set of methods) and likewise monitored/assessed. Based on the monitored performance, one or more alternate method(s) may be substituted for the original method(s) in the program code file. Such a capability allows for methods to be evaluated during runtime, and for performance to be optimized by utilizing the highest performing methods.