I'm writing an Android Service to detect when an image is captured using the camera. Once it's captured I need to get the image contents into a byte array.

Here are the important parts of the onStartCommand method of the Service:

@Override
public int onStartCommand(Intent intent, int flags, int startId) {
    String imgsPath = Environment.getExternalStorageDirectory().getAbsolutePath() + "/DCIM/Camera";
    
    // fileObserver is an instance variable so that it doesn't get garbage collected after onStartCommand runs
    this.fileObserver = new FileObserver(imgsPath, FileObserver.ALL_EVENTS) {
        @Override
        public void onEvent(int event, @Nullable String path) {
            
            if (event != FileObserver.CREATE)
                return;

            byte[] bytes = new byte[0];
            String filePath = imgsPath + "/" + path;

            try {
                bytes = org.apache.commons.io.FileUtils.readFileToByteArray(new File(filePath));
            } catch (IOException e) {
                e.printStackTrace();
            }
            // ... additional unimportant things for this question.
        }
    };
    this.fileObserver.startWatching();
    return START_STICKY; // If service gets killed, after returning from here then restart
}

onEvent runs whenever I capture an image with the camera. However, when I attempt to read the file into a byte array (the LOC in the try does this), I receive the following exception/stack trace:

W/System.err: java.io.IOException: File '/storage/emulated/0/DCIM/Camera/.pending-1642979007-20220116_150327.jpg' cannot be read
W/System.err:     at org.apache.commons.io.FileUtils.openInputStream(FileUtils.java:294)
W/System.err:     at org.apache.commons.io.FileUtils.readFileToByteArray(FileUtils.java:1851)

My hunch is that as the file is being written to the system (all the bytes aren't saved to the disk yet) that the .pending-1642979007-20220116_150327.jpg file is used, and then renamed to 20220116_150327.jpg. Is this the typical, or guaranteed behaviour of the Android OS? Stepping through the debugger I don't see another CREATE event for the 20220116_150327.jpg file.

If I want to only deal with the file once it's in a non-pending file state (everything has been written to disk) how should I do this? Is detecting the renaming of the .pending file how it should be done?