// ( Found on https://stackoverflow.com/questions/4440479/how-can-i-add-jar-files-to-the-web-inf-lib-folder-in-eclipse#:~:text=Up%20vote%200-,Add%20the%20jar%20file%20to%20your%20WEB%2DINF%2Flib%20folder,are%20included%20on%20the%20classpath. )
// Right click -> Properties
// Project Facets -> Check Dyanmic Web Module and Java Version
// Apply Setting.