The IDEs usually compile the code for analysis to help us spot syntax errors or undefined classes and methods on the fly. This compilation is usually partial, covering a part of the code, and as it runs all the time, the source code changes and is never actually complete. To create the deployable file, that is, the final deliverable code of the project, a separate build process has to be started. Most of the IDEs have some built-in tool for that, but it's not recommended to use these, except for the smallest projects. Professional development projects use Ant, Maven, or Gradle instead.
Here's an example of Maven:
The IDEs are prepared to use such an external tool, and they can help us start them. This way, ...
