I downloaded the "JRA_FlightBooking.zip" from https://www.sdn.sap.com/irj/sdn/developerareas/java?rid=/webcontent/uuid/7d646a6c-0501-0010-b480-bf47b8673143">webas [original link is broken] [original link is broken] for the tutorial "Accessing BAPIs Using the SAP Java Resource Adapter". But, the zip file doesn't extract and the log says, "<b>End-of-central-directory signature not found. Either this file is not a Zip file, or it constitutes one disk of a multi-part Zip file.</b>".
Does anyone know if this zip can be downloaded from somewhere else?
Install WinRar and then try to unpack this zip. Might work.
Worked for me.