How do I use

java.util

class like

HashSet

,

ArrayList

or

SortedSet

in my POJO without having to use Kyro? The warnings I get when I try this:

class java.util.ArrayList does not contain a setter for field size
Class class java.util.ArrayList cannot be used as a POJO type because not all fields are valid POJO fields, and must be processed as GenericType. Please read the Flink documentation on "Data Types & Serialization" for details of the effect on performance and schema evolution.

and

No fields were detected for class java.util.HashSet so it cannot be used as a POJO type and must be processed as GenericType. Please read the Flink documentation on "Data Types & Serialization" for details of the effect on performance and schema evolution.

I read through the documentation and stackoverflow and the conclusion is that I need to make a TypeInfoFactory and use it inside a TypeInfo annotation over my POJO. While this seems incredibly tedious since I have a bunch of POJOs in my project, I would be fine with this solution if I could figure out how to do this for the

Set

types I'm using. Any help would be appreciated.

Hi @Saleh, I also encountered same issue as far as I have investigated there is no work around rather than implementing type-factory.

Hi @Keyur Makwana, Thanks. Do you happen to have an example of a type factory for Sets?

Not exactly but you can try replacing list with Set in below code,

public class ResourceTypeFactory extends TypeInfoFactory<Log> {
    @Override
    public TypeInformation<Log> createTypeInfo(Type type, Map<String, TypeInformation<?>> map) {
        return Types.POJO(Log.class,ImmutableMap.<String, TypeInformation<?>>builder()
                        .put("resources", Types.LIST(Types.POJO(Resource.class)))
                        .put("version",Types.STRING)
                        .put("user", Types.POJO(User.class))
                .build()
        );
    }
}

Sorry, I'm not really sure how to do that. I can't find

SET

in the

Types

package.

I have also not much of idea about SET