How to delete all datastore in Google App Engine?

Question

Does anyone know how to delete all datastore in Google App Engine?

Answer 1

For java

DatastoreService db = DatastoreServiceFactory.getDatastoreService();
List keys = new ArrayList();
for(Entity e : db.prepare(new Query().setKeysOnly()).asIterable())
    keys.add(e.getKey());
db.delete(keys);

Works well in Development Server