open every file in a specific folder than open all of them and write "Coded by Inventex" to the first line as a comment

import java.io.File;

File folder = new File("C:\\Users\\Inventex\\Documents");
File[] listOfFiles = folder.listFiles();

for (File file : listOfFiles) {
    if (file.isFile()) {
        System.out.println(file.getName());
    }
}