Create a File object, passing the directory path to the constructor. Use the listFiles() to retrieve an array of File objects for each file in the directory, and then call the getName() method to get the filename.
List<String> results = new ArrayList<String>();
File[] files = new File("/path/to/the/directory").listFiles();
//If this pathname does not denote a directory, then listFiles() returns null.
for (File file : files) {
if (file.isFile()) {
results.add(file.getName());
}
}