I want to figure out a way to Read anExcel,CSV File from external location, and get each row values on a pagelist property. It is better without using listner since it is only for OneTimeActivity. If possible using Java it would be better.
Yes, it is possible by Java. Please explore PRFile in pega engine api which let you access file from a directory. If you are dealing with excel and need more granular control apache POI comes OOTB with pega.