How do you deal with computation during Java application development?
When developing Java application, we may encounter computation similar to database computation. For example, there are 2 frequently-updated Excel sheets, the client data and the orders. By inputting a dynamic product list, to find out which clients in the Excel sheet have bought all products in the list.
The "similar to database computation" refers to computation on the structured data of an application without database. Although Java code is capable of handling such computation, the computation procedure is very cumbersome and verbose. Then, how to implement such computations in Java conveniently?