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https://issues.apache.org/jira/browse/IGNITE-12468?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17029056#comment-17029056
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Ivan Pavlukhin commented on IGNITE-12468:
-----------------------------------------
[~alex_pl], I checked some corner cases and found 2 generally unpleasant
things.
List having a direct reference to itself among elements leads to
{{StackOverflowError}}.
{code}
List<Object> l = new ArrayList<>();
l.add(l);
{code}
List having indirect self-reference leads to creation of 2 list objects instead
of only one as was initially.
{code}
List<Object> l = new ArrayList<>();
l.add(new Wrapper(l));
{code}
I.e. after put/get into a cache we will receive a top level _list1_ containing
a _wrapper_ wrapping _list2_. _list2_ will contain the same _wrapper_.
Good news for us are that both peculiarities takes place for a thick client as
well.
Additionally, I noticed a following. In PR there are changes on a
{{ClientUtils#readObject}} execution path handling nested deserialization of
collections. And as I understood it has an effect only for top-level
collections (a value inserted into a cache is a collection). If a collection is
wrapped into binary object, then a collection deserialization will go another
path. And actually it looks like a duplication again. In my mind we need 2
things here. Fist is a justification of the duplication if it is unavoidable.
Second is tests ensuring that thin and thick client behave the same.
> ClassCastException on thinClient in Apache Ignite
> -------------------------------------------------
>
> Key: IGNITE-12468
> URL: https://issues.apache.org/jira/browse/IGNITE-12468
> Project: Ignite
> Issue Type: Bug
> Components: binary, clients, thin client
> Affects Versions: 2.6
> Reporter: LEE PYUNG BEOM
> Assignee: Aleksey Plekhanov
> Priority: Major
>
>
> {code:java}
> ClientConfiguration cfg = new
> ClientConfiguration().setAddresses("127.0.0.1:10800");
> try (IgniteClient igniteClient = Ignition.startClient(cfg)) {
> System.out.println(">>> Thin client put-get example started.");
> final String CACHE_NAME = "put-get-example";
> ClientCache<Integer, Object> cache =
> igniteClient.getOrCreateCache(CACHE_NAME);
> Person p = new Person();
> //put
> HashMap<Integer, Person> hm = new HashMap<Integer, Person>();
> hm.put(1, p);
> cache.put(1, hm);
> //get
> HashMap<Integer, Person> map = (HashMap<Integer, Person>)cache.get(1);
> Person p2 = map.get(1);
> System.out.format(">>> Loaded [%s] from the cache.\n",p2);
> }
> catch (ClientException e) {
> System.err.println(e.getMessage());
> e.printStackTrace();
> }
> catch (Exception e) {
> System.err.format("Unexpected failure: %s\n", e);
> e.printStackTrace();
> }
> {code}
>
> I use the thin client of apache-ignite.
> I Create a hashmap and put the Person
> class(org.apache.ignite.examples.model.Person) object into it.
> And when I take it out of the hashmap, I get the following exceptions:
>
> {code:java}
> > java.lang.ClassCastException:
> > org.apache.enite.internal.binary.BinaryObjectImpl cannot be cast to
> > org.apache.engite.examples.model.Person.
> {code}
> An exception is given in the code below.
>
> {code:java}
> Person p2 = map.get(1);
> {code}
>
> However, there is no exception if I modify the code as follows:
>
> {code:java}
> BinaryObject bo = (BinaryObject) map.get(1);
> Person p2 = bo.deserialize();
> {code}
> I don't think that's necessary. Is there another solution?
>
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