### Question:
UtilFile { public static boolean isFile(String path) { return path != null && new File(path).isFile(); } private  UtilFile(); static String removeExtension(String file); static String normalizeExtension(String file, String extension); static String getExtension(String file); static String getExtension(File file); static List<File> getFiles(File directory); static List<File> getFilesByExtension(File path, String extension); static List<File> getFilesByName(File path, String name); static void deleteFile(File file); static boolean exists(String path); static boolean isFile(String path); static boolean isType(File file, String extension);  }### Answer:
@Test void testIsFile() throws IOException { assertFalse(UtilFile.isFile(null)); final File file = Files.createTempFile("temp", ".tmp").toFile(); assertTrue(UtilFile.isFile(file.getPath())); assertTrue(file.delete()); assertFalse(UtilFile.isFile(file.getPath())); }