ABAP (Advanced Business Application Programming) is that the name of SAP’s proprietary, fourth-generation programing language. it had been specifically developed to permit the mass processing of knowledge in SAP business applications.

By working with ABAP in SAP NetWeaver, companies running the SAP ERP and 
SAP S/4HANA business solutions have the chance to customize those systems 
to raised meet their needs.

ABAP may be a multi-paradigm programing language , meaning programmers can utilize procedural, object-oriented, and other programming principles. While it's SAP’s 
primary programing language , programs written with ABAP can run alongside those 
supported other programming languages like Java, JavaScript, and SAPUI5.

https://www.sevenmentor.com/sap-abap-course-in-pune.php