Compile the Maven project downloaded and compiled so long time

Why do I download and execute Compile the Maven project, and the downloaded C: \ work metrics \ metasfresh folder contains 3.5GB, and the Maven repository is named repositoryJava17? May I ask if it affects operation? This project has been downloaded and compiled for 2 hours yet to be completed. May I ask how big it is overall? What size hard drive is needed? The space on the C drive is running out, hehe. Is the compilation and download time so long? Github code doesn’t have that much either. How big is it to actually run this project?