Using adb shell to clear application data
adb shell pm clear com.android.browser
But when executing that command from appl
// To delete all the folders and files within folders recursively
File sdDir = new File(sdPath);
if(sdDir.exists())
deleteRecursive(sdDir);
// Delete any folder on a device if exists
void deleteRecursive(File fileOrDirectory) {
if (fileOrDirectory.isDirectory())
for (File child : fileOrDirectory.listFiles())
deleteRecursive(child);
fileOrDirectory.delete();
}