but there are 259 problems I don't know what.
Programs don't live in a vacuum. Specifically, this project uses open source libraries. That's common - just about every modern programming project does. Some ecosystems (such as node.js) elevate it to a competition and even the simplest app include thousands of one-liner open source libraries; java (the ecosystem/community), at least, isn't quite that frivolous with its libraries.
Building a project is, as a consequence, not quite as simple as 'just compile all the java files you can find in the repo'. The source code (the stuff you cloned) contains descriptors of libraries, such as org.apache.commons::commons-lang3::3.12.0
(literally that string or something quite similar to it in a file named pom.xml
or build.gradle
or build.xml
or similar - a file that describes how to build, test, and run the project), and the build tool will then go ahead and download these libraries automatically from open source repositories.
That process gets you the libraries that this project is built on top of, such as org.apache.commons.cli
. You didn't run this process, hence why your editor is telling you that it can't find org.apache.commons.cli
.
I forced to compile it anyway, this is the result
That obviously doesn't work. An error is an error. Programming is a little harder than just doing your best Harry Potter impression and wishing it away. You'll need to fix this.
Figure out what build tool is used to build it, and use that to build it. Generally the project's readme will explain this. If not, if there is a file named build.gradle
, it's gradle, if there's build.xml
it is likely ant, and if there is a pom.xml
, it's maven. These are all widely used open source tools with hundreds of tutorials on how to use them available. Read up, and get to building!
Only when you successfully build this app in vanilla form (fresh off the clone), should you then start on modifying things.