### Question:
AjaxUpload extends AbstractField { void onRemoveUpload(int serverIndex) { if (value != null && serverIndex >= 0 && serverIndex < value.size()) { UploadedFile item = value.get(serverIndex); if (item != null && (item instanceof UploadedFileItem)) { ((UploadedFileItem) item).cleanup(); } value.set(serverIndex, null); } } AjaxUpload();   AjaxUpload(List<UploadedFile> value, FieldValidator<Object> validate, MultipartDecoder multipartDecoder,
         AjaxUploadDecoder ajaxDecoder, ValidationTracker tracker, ComponentResources resources,
         FieldValidationSupport fieldValidationSupport, JavaScriptSupport javaScriptSupport); List<UploadedFile> getValue(); @Override boolean isRequired(); void injectFieldValidationSupport(FieldValidationSupport support); static final String FILE_PARAMETER; }### Answer:
@Test public void check_on_remove_works_for_null_value() { AjaxUpload component = new AjaxUpload(); component.onRemoveUpload(0); }