[Demonstration 1]

[Buggy Method]
public void saveChanges() {
    if (!isDataChanged)
        return;
    List<String> savedYMList = new ArrayList<>(changedItemYMList.size());
    itemSaveFileManager.updateSaveFiles();
    for (String ym : changedItemYMList) {
        List<Item> itemsToSave = itemData.getItems(ym);
        String fileName = ItemSaveFileManager.getSaveFileName(ym);
        //if item list is empty, delete the ym file.
        if (itemsToSave.isEmpty()) {
            //necessary line for the below deleteFile()
            itemSaveFileManager.updateSaveFiles();
            if (itemSaveFileManager.deleteFile(ym, false)) {
                savedYMList.add(ym);
                System.out.println("correctly deleted " + fileName + " .");
            } else {
                System.err.println("could not delete " + fileName + ".");
            }
        } else //if item list is not empty and the save succeeded.
        if (itemSaveFileWriter.saveItemsToSaveFile(false, ym, itemsToSave)) {
            savedYMList.add(ym);
            System.out.println("correctly saved @ " + fileName + " .");
        } else {
            System.err.println("could not correctly save2 @ " + fileName + " .");
        }
    }
    //remove saved ym list
    for (String ym : savedYMList) {
        changedItemYMList.remove(ym);
    }
    itemSaveFileManager.updateSaveFiles();
    setIsDataChanged(false);
}

[Buggy Hunk]
List<Item> itemsToSave = itemData.getItems(ym);

[Patch]
List<Item> itemsToSave = itemData.getItems(ym, true);

[Demonstration 2]

[Buggy Method]
@Override
public int getCount() {
    return titles.size();
}

[Buggy Hunk]
return titles.size();

[Patch]
return VertretungsData.getsInstance().getTagList().size();

[Demonstration 3]

[Buggy Method]
@Override
public int getRowCount() {
    return BackendService.getAuthorManager().findAllAuthors().size();
}

[Buggy Hunk]
return BackendService.getAuthorManager().findAllAuthors().size();

[Patch]
return rowCount;