private ComboBox.List<String> componentcatagaories;

Object[] catagaories = new String[]{"test1", "test2", "test3"};
        componentcatagaories =  new ComboBox.List(5, 20, catagaories);
        this.componentcatagaories.setChangeListener((oldValue, newValue) -> {
                    if (newValue != oldValue) {
                        if (newValue.equals("test1")) {

                        }
                        if (newValue.equals("test2")) {

                        }
                        if (newValue.equals("test3")) {

                        }
                    }
                });