SAP ABAP DevelopersFront End: SAP UI5 / Fiori HTML/JavascriptBack End: ABAP Objects / ABAP OO, O Data Services, CDS VIEWS, SAP BOPF (Business Objects Processing Framework) SAP RAP (Restful Application Programming Model).
*** Classic ABAP will not help, some buzz on classic ABAP: ALV, BAOI /BAPI, IDOC's, Netweaver, SAP ECC, SAP R/3, SAP Script