The difference between new Package/source Folder/folder in eclipse

Package: Language-level packages, source code inside the path
SOURCE folder: The path of the compiled lookup, which calculates the initial location of the package as the base of this folder, and joins the classpath when compiling
Folder: A plain file that is considered a resource file.

Under Eclipse, Package,source Folder,folder are all folders.
The differences are as follows:
Package: When you build a package, it is automatically built into the source folder and can only be built under this directory.

SOURCE folder: Folders that store Java source code, and of course include some package folders, and can contain other files as well.
After the project is built, the Java in the source folder is automatically compiled into a class file into the corresponding Bin folder, and the other files are moved to the appropriate directory.

Folder: It can be placed in any file. Includes Java source files, jar files, other files (e.g., pictures, sounds, etc.). Here I explain that if there is a Java source file inside, regardless of whether the program is correct, Eclipse will not error, Treat them as ordinary files. But if the project is to use the files in it, the situation will be different.