Java Utililty Methods File Extension Name Get

int pos;
String filename;
filename = file.getName();
pos = filename.lastIndexOf('.');
if (pos >= 0) {
    return filename.substring(pos + 1);
} else {
    return "";
...

String filePath = file.getPath();
int index = filePath.lastIndexOf(DOT);
if (index >= 0)
    return filePath.substring(index + 1);
else
    return "";

String fileName = file.getName();
if (fileName.lastIndexOf(".") != -1 && fileName.lastIndexOf(".") != 0)
    return fileName.substring(fileName.lastIndexOf(".") + 1);
else
    return "";

String fileName = file.getAbsolutePath();
String ext = (fileName.lastIndexOf(".") == -1) ? ""
        : fileName.substring(fileName.lastIndexOf(".") + 1, fileName.length());
return ext;

return getFileExtension(file.getName());

if (file == null) {
    return null;
if (!file.getName().contains(".")) {
    return null;
return file.getName().substring(file.getName().lastIndexOf('.') + 1);

String path = file.toString();
if (path == null) {
    return null;
String fileExtension = path.substring(path.lastIndexOf('.') + 1);
return fileExtension;

if (file == null)
    return null;
int extPos = file.getAbsolutePath().lastIndexOf(".");
int sepPos = file.getAbsolutePath().lastIndexOf(File.pathSeparator);
if (extPos == -1)
    return null;
if (sepPos > extPos)
    return null;
...

String fileName = file.getName();
int position = fileName.lastIndexOf('.');
if (position == -1)
    return null;
return fileName.substring(position + 1);

return getFileExtension(file.getName(), includeDot);