Can I see the exact commands IntelliJ uses to build a java project?
IDEA is not running java binary, so there is no way to see the commands. Instead, IDEA uses Java compiler API directly. If you want a raw representation of what is done to build the project, you can use Build | Generate Ant build. Examine the build file or run it from the command line via Ant to see what happens and what options/commands are invoked.