taskEntity = GWT.create(Task.class);
tagEntity = GWT.create(Tag.class);
categoryEntity = GWT.create(Category.class);
Persistence.schemaSync(new Callback() {
@SuppressWarnings("deprecation")
public void onSuccess()
{
destroyAllData(new Callback() {
@Override
public void onSuccess() {
final Category c = categoryEntity.newInstance();
c.setName("Main");
final Tag tag = tagEntity.newInstance();