code: private File[] accept(File file, final boolean recursive) {
          // Custom filtering rules If you can loop (include subdirectories) or is the end of the file. Class (compiled java class file)
          return file.listFiles(file1 -> (recursive && file1.isDirectory()) || (file1.getName().endsWith(".class")));
      }
docs: Filter the file rules
  
  @param file
  @param recursive
  @return