[Demonstration 1]

[Buggy Method]
public static void DeleteMessage(ProfNetwork esql, String currentUser, String type) {
    System.out.print("Please enter the message id that you would like to delete: ");
    try {
        String input = esql.in.readLine();
        int msgid = Integer.parseInt(input.trim());
        try {
            if (type.equals("send")) {
                String query = String.format("SELECT delete_status FROM message WHERE msgid = '%s' AND senderid = '%s'", msgid, currentUser);
                List<List<String>> result = new ArrayList<List<String>>();
                result = esql.executeQueryAndReturnResult(query);
                try {
                    if (result.get(0).get(0).equals("0")) {
                        query = String.format("UPDATE message set delete_status = '1' WHERE msgid = '%s'", msgid);
                        esql.executeUpdate(query);
                    } else {
                        query = String.format("DELETE FROM message WHERE msgid = '%s'", msgid);
                        esql.executeUpdate(query);
                    }
                } catch (Exception e) {
                    System.err.println(e.getMessage());
                }
            } else {
                String query = String.format("SELECT delete_status FROM message WHERE msgid = '%s' AND receiverid = '%s'", msgid, currentUser);
                List<List<String>> result = new ArrayList<List<String>>();
                result = esql.executeQueryAndReturnResult(query);
                try {
                    if (result.get(0).get(0).equals("0")) {
                        query = String.format("UPDATE message SET delete_status = '2' WHERE msgid = '%s'", msgid);
                        esql.executeUpdate(query);
                    } else {
                        query = String.format("DELETE FROM message WHERE msgid = '%s'", msgid);
                        esql.executeUpdate(query);
                    }
                } catch (Exception e) {
                    System.err.println(e.getMessage());
                }
            }
        } catch (Exception e) {
            System.err.println(e.getMessage());
        }
    } catch (Exception e) {
        System.err.println(e.getMessage());
    }
}

[Buggy Hunk]
System.err.println(e.getMessage());

[Patch]
System.out.println("Please enter a valid message id.");

[Demonstration 2]

[Buggy Method]
private void saveData() {
    EditText eventNameView = (EditText) findViewById(R.id.event_name);
    EditText eventDescView = (EditText) findViewById(R.id.event_desc);
    TextView eventTimeView = (TextView) findViewById(R.id.event_time);
    Calendar cal = Calendar.getInstance();
    cal.setTime(new Date());
    String[] timeParts = String.valueOf(eventTimeView.getText()).split(":");
    cal.set(Calendar.HOUR_OF_DAY, parseInt(timeParts[0].trim()));
    cal.set(Calendar.MINUTE, parseInt(timeParts[1].trim()));
    cal.set(Calendar.AM_PM, timeParts[2].trim() == "AM" ? 0 : 1);
    Event event = new Event(eventNameView.getText().toString(), eventDescView.getText().toString(), cal.getTime(), cal.getTime(), 4);
    DatabaseHelper dbHelper = new DatabaseHelper(getApplicationContext());
    EventEntryDAO eventEntryDAO = new EventEntryDAO(dbHelper.getWritableDatabase());
    EventBackupTimeDAO eventBackupTimeDAO = new EventBackupTimeDAO(dbHelper.getReadableDatabase());
    eventEntryDAO.insert(event);
    eventBackupTimeDAO.insert(4, new Date(System.currentTimeMillis()));
    dbHelper.close();
}

[Buggy Hunk]
cal.set(Calendar.HOUR_OF_DAY, parseInt(timeParts[0].trim()));

[Patch]
cal.set(Calendar.HOUR, parseInt(timeParts[0].trim()));

[Demonstration 3]

[Buggy Method]
private int getNewId() {
    int maxId = 0;
    if (lists.size() > 0) {
        java.util.List<Integer> ids = new ArrayList<Integer>();
        for (List item : lists) {
            ids.add(item.getId());
        }
        maxId = Collections.max(ids);
    }
    return maxId + 1;
}

[Buggy Hunk]
java.util.List<Integer> ids = new ArrayList<Integer>();

[Patch]
java.util.List<Integer> ids = new ArrayList<>();