I'm working in JAVA now, and I want to switch to SAP. I don't know which module is better to learn. Please recommend one for me. Thank you.

SAP is the world's largest enterprise information management solution provider and the largest ERP product manufacturer. Its full name is the system application and product in data processing, and it is also the software name of one of its "enterprise management solutions". The functional classification of SAP [1] includes:

FI Accounts receivable, accounts payable, general ledger, merger, investment, funds, cash, etc. ;

CO profit and cost center, product cost, project accounting and profit analysis.

AM fixed assets, technical assets, investment control, etc.

SD sales plan, inquiry and quotation, order management, transportation and delivery, invoices, etc.

MM procurement, warehouse management, inventory management, MRP, supplier evaluation, etc.

PP factory data, production planning, MRP, capacity planning, cost accounting, etc.

QM quality plan, quality inspection, quality control, quality documents, etc.

Preventive maintenance and inspection plan, document processing, historical data, report analysis, etc.

HR salary, travel, working hours, recruitment, development plan, personnel expenses, etc.

PS project planning, budget, capacity planning, resource management, result analysis, etc.

WF work definition, process management, e-mail, information transmission automation, etc.

Integration of PI SAP with other systems;

It provides special applications for different industries.

Basic parts: R/3 system kernel, database, interfaces supporting various platforms, ABAP/4 tool language, etc.

The only thing that doesn't exist here is BW, because BW is a non-ERP software in SAP and a new module of SAP. I suggest you learn BW, the salary is very high.