[Demonstration 1]

[Buggy Method]
@Override
public void onErrorResponse(VolleyError error) {
    Toast.makeText(getApplicationContext(), "Error in request: " + error.getMessage(), Toast.LENGTH_LONG);
}

[Buggy Hunk]
Toast.makeText(getApplicationContext(), "Error in request: "+ error.getMessage(), Toast.LENGTH_LONG);

[Patch]
Toast.makeText(getApplicationContext(), "Error in request: "+ error.getMessage(), Toast.LENGTH_LONG).show();

[Demonstration 2]

[Buggy Method]
@Override
public void onSearchButtonClick() {
    if (!subscription.isUnsubscribed()) {
        subscription.unsubscribe();
    }
    subscription = mainModel.getProjects().subscribe(new Observer<List<ProjectDTO>>() {

        @Override
        public void onCompleted() {
        }

        @Override
        public void onError(Throwable e) {
            view.showError(e.getMessage());
        }

        @Override
        public void onNext(List<ProjectDTO> data) {
            if (data != null && !data.isEmpty()) {
                view.showData(data);
            } else {
                view.showEmptyList();
            }
        }
    });
}

[Buggy Hunk]
subscription = mainModel.getProjects()

[Patch]
subscription = previewMapper.previews()

[Demonstration 3]

[Buggy Method]
private static void saveImage(Context context, Bitmap image, String fileName) throws IOException {
    FileOutputStream outputStream;
    ContextWrapper cw = new ContextWrapper(context);
    final File imagesDirectory = cw.getDir(IMAGES_DIRECTORY_NAME, Context.MODE_PRIVATE);
    File imageFile = new File(imagesDirectory, fileName);
    outputStream = new FileOutputStream(imageFile);
    switch(getFileExtension(fileName).toUpperCase()) {
        case "JPEG":
            image.compress(Bitmap.CompressFormat.JPEG, IMAGE_QUALITY, outputStream);
            break;
        case "JPG":
            image.compress(Bitmap.CompressFormat.JPEG, IMAGE_QUALITY, outputStream);
            break;
        case "PNG":
            image.compress(Bitmap.CompressFormat.PNG, IMAGE_QUALITY, outputStream);
            break;
    }
    outputStream.close();
}

[Buggy Hunk]
outputStream = new FileOutputStream(imageFile);

[Patch]
outputStream = new FileOutputStream(imageFile, false);