Java: How to get only subdirectories name present at certain level?

Question

Here is my folder structure:

parent/
  child1/
    child1.1/
    child1.2/
  child2/
    child 2.1/
    child 2.2/
  child3/
    child 3.1/
    child 3.2/

How can I extract only the names of the third-level folders? (I haven't been able to find this online)

Output should be:

child1.1 ,child1.2 
child2.1 ,child2.2
child3.1 ,child3.2

I referenced Java: how to get all subdirs recursively? to find subdirectories.

Answer 1

To make level parametric I suggest code:

static public List<File> getDirs(File parent, int level){
    List<File> dirs = new ArrayList<File>();
    File[] files = parent.listFiles();
    if (files == null) return dirs; // empty dir
    for (File f : files){
        if (f.isDirectory()) {
             if (level == 0) dirs.add(f);
             else if (level > 0) dirs.addAll(getDirs(f,level-1));
        }
    }
    return dirs;
}

And call it:

List<File> l = getDirs(new File("/some/path"), 3);

Edit: I added verification in case of empty directory