Java Utililty Methods Folder Read by Extension

String[] children = baseDir.list();
if (children == null) {
} else {
    for (String filename : children) {
        File file = new File(baseDir, filename);
        if (filename.endsWith(validExtension)) {
            files.add(file);
        } else {
...

if (dir == null)
    return new File[0];
File[] list = dir.listFiles(new FilenameFilter() {
    @Override
    public boolean accept(File dir, String name) {
        return name.toLowerCase().endsWith(extension);
});
...

Map<String, File> names = new HashMap<String, File>();
if (dir == null || !dir.exists() || !dir.isDirectory()) {
    return names;
File[] files = dir.listFiles(new FilenameFilter() {
    public boolean accept(File dir, String name) {
        return name.toLowerCase().endsWith("." + extension);
});
for (File file : files) {
    names.put(file.getName().substring(0, file.getName().length() - extension.length() - 1), file);
return names;

return dir.listFiles(new FilenameFilter() {
    public boolean accept(File dir, String name) {
        return name.toLowerCase().endsWith("." + extensionFilter);
});

File[] files = dir.listFiles((f, s) -> s.endsWith(fileExtension));
return Arrays.asList(files);

final Set<String> exts = new HashSet<String>();
for (String ext : extensions) {
    exts.add(ext.toLowerCase());
File[] files = folder.listFiles(new FileFilter() {
    @Override
    public boolean accept(File file) {
        if (file.isDirectory()) {
...

final File folder = new File(path);
final File[] listOfFiles = folder.listFiles();
final ArrayList<File> theFiles = new ArrayList<File>();
for (final File f : listOfFiles) {
    if (f.isFile()) {
        if (f.getName().substring(f.getName().lastIndexOf(".")).equalsIgnoreCase(ext)) {
            theFiles.add(f);
System.out.println("Found files " + theFiles);
return theFiles;

List matchedFiles = new ArrayList();
File fileDir = new File(dir);
if (fileDir.exists()) {
    String[] files = fileDir.list();
    for (int i = 0; i < files.length; i++) {
        if (files[i].endsWith(ext))
            matchedFiles.add(files[i]);
return matchedFiles;

File f = new File(dir);
if (!f.isDirectory()) {
    return null;
List<File> fileList = new ArrayList<File>();
getFiles(f, fileList, extension);
return fileList;

List<String> fileNames = new ArrayList<>();
try {
    File f = new File(directory);
    boolean flag = f.isDirectory();
    if (flag) {
        File fs[] = f.listFiles();
        for (int i = 0; i < fs.length; i++) {
            if (!fs[i].isDirectory()) {
...