If you already know Java, then the obvious choice is the Vaadin Framework.
Vaadin lets you rapidly develop a web app user-interface using only pure Java. Your app lives on the server-side, where you specify fields, labels, buttons, data grids, and other widgets arranged in layouts using only Java code.
Vaadin is free-of-cost and open-source. In addition, the company Vaadin Ltd does sell a spreadsheet add-on if you need it. But the built-in powerful and flexible Grid widget may suffice from what I can seen in that screenshot you posted.
For a database, you can use anything with a JDBC driver. You might want to use the H2 Database Engine. It is built in pure Java, and is free-of-cost, open-source, and actively developed. But if you need heavy-duty enterprise-level performance, features, and reliability, then Postgres.