In fact, most large ERP systems use java.
Most small and medium-sized enterprises use C#, which has the advantages of fast development, fast natural collection and fast withdrawal of funds.
The foreground is C# and the background is java. After all, java is cross-platform, and demanding servers need C# of unix/linux, so the background is generally java, and the foreground depends on the situation.
Then you can judge for yourself.
ERP implementation seems to be written in a language you don't care about. After people write the program, test it and sell it to customers, they sign a contract, which is to install it for customers. Customers with problems will contact you, give feedback, develop and modify, and then you can implement the upgrade. You don't need to know anything in the program.
It belongs to the after-sales category, and needs to be familiar with this product business and be able to answer customers' questions and so on.