/* package whatever; // don't place package name! */
 
import java.util.*;
import java.lang.*;
import java.nio.file.*;
 
/* Name of the class has to be "Main" only if the class is public. */
class Ideone
{
	public static void main (String[] args) throws java.lang.Exception
	{
		String result = transform("/some/path/to/some/dir");
		System.out.println(result);
	}
 
	private static String transform(String p) {
		Path path = Paths.get(p);
		int nameCount = path.getNameCount();
		if (nameCount < 2) throw new RuntimeException();
		return String.format("%s_%s", path.getName(nameCount-2), path.getName(nameCount-1));
	}
}

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