[Demonstration 1]

[Buggy Method]
@Subscribe
public void onRefreshFinished(final ExchangeRateRequest request) {
    if (model != null && model.getCode().equals(request.getFromCode())) {
        loadingView.post(new Runnable() {

            @Override
            public void run() {
                setRefreshing(false);
                final Currency currency = request.getCurrency();
                if (currency != null) {
                    model.setExchangeRate(currency.getExchangeRate());
                    onModelLoaded(model);
                }
            }
        });
    }
}

[Buggy Hunk]
if (model != null && model.getCode().equals(request.getFromCode())) {

[Patch]
if (model != null && !StringUtils.isEmpty(model.getCode()) && model.getCode().equals(request.getFromCode())) {

[Demonstration 2]

[Buggy Method]
public void highlight(ActionEvent e) {
    JEditorPane editor = getEditor(e);
    if (editor != null) {
        StyledEditorKit kit = getStyledEditorKit(editor);
        MutableAttributeSet attr = kit.getInputAttributes();
        javax.swing.text.DefaultHighlighter.DefaultHighlightPainter highlightPainter = new javax.swing.text.DefaultHighlighter.DefaultHighlightPainter(Color.YELLOW);
        try {
            editor.getHighlighter().addHighlight(editor.getSelectionStart(), editor.getSelectionEnd(), highlightPainter);
        } catch (BadLocationException e1) {
            // TODO Auto-generated catch block
            e1.printStackTrace();
        }
    }
}

[Buggy Hunk]
editor.getHighlighter().addHighlight(editor.getSelectionStart(), editor.getSelectionEnd(), highlightPainter);

[Patch]
last = editor.getHighlighter().addHighlight(editor.getSelectionStart(), editor.getSelectionEnd(), highlightPainter);

[Demonstration 3]

[Buggy Method]
@Test
public void testgetEmptyField() {
    Field free0 = board.getEmptyField(1, 1);
    Field expected0 = new Field(1, 1, 0);
    assertEquals(expected0, free0);
    board.setField(free0, Mark.Black);
    Field free1 = board.getEmptyField(1, 1);
    Field expected1 = new Field(1, 1, 1);
    assertEquals(expected1, free1);
}

[Buggy Hunk]
board.setField(free0, Mark.Black);

[Patch]
board.setField(free0, Mark.X);