I would like to build a graphical application that must work on at least Windows, Linux and MacOS. I would like to know what do you suggest I should use.
I have some experience with Java and C++ but I thought about using Java Swing first. What do you think or further suggest (like maybe tools or frameworks)? I also may be needing to connect to a PostgreSQL database to store data.
Java is probably the simplest way to get your application working on all 3 platforms as well as to add database support. All of these are equally possible in C++, but it definitely involves more work because you need to learn to use a cross-platform widget toolkit. Also, C++ database drivers usually have wildly varying designs but Java presents a unified interface via JDBC – this also means that you can change your underlying DB at any time without having to change your code.