How can ChatGPT analyze multiple files?

Dear ChatGPT Experts,

Currently, suppose I have a Java file that I need ChatGPT to analyze it, I need to copy all the lines in the Java file and paste it in the input box and press Enter for ChatGPT to analyze.

However, there is a limit that ChatGPT can only take up to certain number of characters (I think 2000 characters?).

Now what can I do if I have multiple files, say 20 files, for ChatGPT to analyze. Is there a way to sink 20 files to a repository and ChatGPT can analyze all the files in this repository?

Thanks!

Kevin