import javax.annotation.processing.SupportedSourceVersion;
import java.io.*;
import java.util.logging.Filter;
public class Main {
public static void main(String[] args) {
String filePath = "pat do datoteka";
File file = new File(filePath);
File[] files = file.listFiles();
long max_length = 0;
File tmp = null;
for(int i = 0; i < files.length; i++) {
if(max_length < files[i].length()) {
max_length = files[i].length();
tmp = files[i];
}
}
System.out.println(tmp.getName());
}
}