Java set of path pretty output in console

Please advice good solution in Java how to pretty print in console Set of java.nio.file.Path.
For example:
Path:

/src/test/resources/TestFolder/Wave.java
/src/test/resources/TestFolder 
/src/test/resources/TestFolder/Mello.java 
/src/test/resources/TestFolder/TestFolder2/Dave2.java 
/src/test/resources/TestFolder/TestFolder2/Hello2.java 
/src/test/resources/TestFolder/TestFolder2

And expected result:

TestFolder 
   Wave.java
   Mello.java 
   TestFolder2 
      Dave2.java 
      Hello2.java 

There is no built in API call that would do this. Fortunately, Java is a programming language, and you're a programmer. Let's program it!

The tools you need:

relativize, or getFileName

You can use the relativize call to produce paths that are relative to a 'root point'. For example:

Paths.get("/src/test/resources").relativize(Paths.get("/src/test/resources/TestFolder/Mello.java"))

turns into a path representing: TestFolder/Mello.java.

However, perhaps you want each entry in your output to always only be just a single file name; in that case, the getFileName() call strips out all path elements except the lasts one: Paths.get("/src/test/resources/TestFolder/TestFolder2/Hello2.java").getFileName() produces a path with just Hello2.java (if you need it as string, just call toString() on the path object to get that).

StringBuilder

The StringBuilder class can be used to produce a longer string piece by piece.

repeat

If you have an int representing your 'nesting level', in your example you want a bunch of spaces in front of the filename equal to some multiple of that. You can use the repeat call to turn a number into a string containing that number of spaces: String prefix = " ".repeat(5); produces a string containing 10 spaces.

NB: This is somewhat newer API; if you're on an old version of java and this call does not work, you'd have to write it yourself. It's just a single for loop.

Files.isDirectory

To know if any given file is a directory, you can call that; it returns true if it is and false if it is not.

Files.newDirectoryStream

This is one way to 'walk' a file system: This lets you list each dir/file in a given directory:

Path somePathObject = Paths.get("/foo/bar");
try (var contents = Files.newDirectoryStream(somePathObject)) {
    for (Path content : contents) {
        .. this is called once for each file/dir in '/foo/bar'
    }
}

recursion

Finally, to tie it all together: You'd want to walk through each child in a given starting point, if it is a file, print a number of spacers equal to our nesting level (which starts at 0), then the simple file name, and then move on to the next entry. For directory entries, you want to do that but then 'dive' into the directory, incrementing the nesting level. If you make the nesting level a parameter, you can call your own method, using the directory as new 'root point', and passing 'nestingLevel + 1' for the nesting level.

Good luck & Have fun!