1. A computer-implemented method for replacing annotated program code in a networked computing environment, comprising: detecting an annotation in a program code file, the annotation comprising a runtime optimization request with a set of criteria for running the program code file; monitoring, responsive to the detecting, at least one method in the program code file during runtime based on the set of criteria; identifying at least one program code library from a code repository and stored in a computer storage device; identifying at least one substitute method for the at least one method, the at least one substitute method being identified from the at least one program code library; monitoring the at least one substitute method based on the set of criteria; and selecting, based on the monitoring of the at least one substitute method, a substitute method from the at least one substitute method for use in the program code file and a substitute program code library from the at least one program code library, the substitute program code library being selected based on a most optimal performance for the detected annotation.