NPE with generated value

[bejayoharen]

I am porting some code and am getting this exception:

Caused by: java.lang.NullPointerException
at com.impetus.kundera.configure.MetamodelConfiguration.processGeneratedValueAnnotation(MetamodelConfiguration.java:452)
at com.impetus.kundera.configure.MetamodelConfiguration.scanClassAndPutMetadata(MetamodelConfiguration.java:370)
at com.impetus.kundera.configure.MetamodelConfiguration.loadEntityMetadata(MetamodelConfiguration.java:227)
at com.impetus.kundera.configure.MetamodelConfiguration.configure(MetamodelConfiguration.java:107)
at com.impetus.kundera.configure.Configurator.configure(Configurator.java:65)
at com.impetus.kundera.KunderaPersistence.initializeKundera(KunderaPersistence.java:109)
at com.impetus.kundera.KunderaPersistence.createEntityManagerFactory(KunderaPersistence.java:81)
at javax.persistence.Persistence.createEntityManagerFactory(Unknown Source)
at javax.persistence.Persistence.createEntityManagerFactory(Unknown Source)
at com.xonami.rest.db.EMFactory.(EMFactory.java:19)
... 61 more

I assuming this has something to do with the @GeneratedValue annotations, but I can't figure out what. I am using mongodb. My annotations look like this:

@Id
@Column
@GeneratedValue(strategy = GenerationType.AUTO)
private String key;

Some of them are annotated with @column, some are not.

[mevivs]

Hi,
Do you need primary key to be auto generated using @GeneratedValue?

-Vivek

[mevivs]

Please refer:
https://github.com/impetus-opensource/Kundera/tree/trunk/kundera-mongo/src/test/java/com/impetus/client/generatedId

for more on usage of @GeneratedValue over MongoDB.

[bejayoharen]

The original code uses it (@GeneratedValues). I'd like to map the original code as closely as possible before changing things, so yes, I need autogenerated primary keys.

[bejayoharen]

That link uses ObjectIds, which are familiar from mongo. It also uses @TableGenerator. The docs here:

https://github.com/impetus-opensource/Kundera/wiki/Primary-Key-Auto-generation

use Strings and no mention of @TableGenerator. I Followed the docs. What do I need to change?

If my usage is not correct:

• the docs should be updated, and
• A correct error message should be displayed rather than a NPE.

[mevivs]

Did you try referrring to:
https://github.com/impetus-opensource/Kundera/tree/trunk/kundera-mongo/src/test/java/com/impetus/client/generatedId

for more on usage of @GeneratedValue over MongoDB.

If yes, and still getting error, please share your code snippet link

-Vivek

[mevivs]

KK,
Please look into this.

-Vivek

[bejayoharen]

"Did you try referrring to:" Yes. As I said, it is different from the docs:

• The Docs use the String type for generated ids, whereas the code you linked to uses ObjectIds.
• The Docs make no mention of @TableGenerator, whereas the code you linked to uses it.

Do I need to change both things, or just the type? I have 19 generated values in my code, so it's a fair bit of code to go over and I'd like to just change the type if that's all I need to change. Moreover:

• Your docs are wrong.
• This should not cause a NPE. it should display a useful error message.

[mevivs]

As per
https://github.com/impetus-opensource/Kundera/wiki/Primary-Key-Auto-generation:

Table generation strategy is only applicable to "Cassandra" and "HBase".

The Docs use the String type for generated ids, whereas the code you linked to uses ObjectIds.

In case, you want _id field in mongodb to be of type ObjectId, then only you need to declare it as "ObjectId" in your entities. If you define them as "String" type, by default _id field in mongodb will persisted as auto generated "ObjectId.toString()", method

Your docs are wrong.

I will get them updated for above mentioned information, Thanks for pointing it out.

This should not cause a NPE. it should display a useful error message.

It should not be thrown and a proper message should have been displayed. I will verify it.

Thanks,
-Vivek

[mevivs]

Version of Kundera referring to? Is it 2.5 or 2.5.1?

-Vivek

[bejayoharen]

• I am using 2.5. I'll try 2.5.1 and will report if it's different.
• I have changed all instances of String to ObjectId and error remains. I cannot share the code, but if I can't get past this I'll try to reproduce on a smaller example, if I can.

[mevivs]

For:

This should not cause a NPE. it should display a useful error message.

Did you specify Entity with @table annotation, as for example:

@Table(name = "PERSON", schema = "keyspace@mongo_pu")

To map it correctly with MongoDB, you need to add this over Entity definition.

-Vivek

[bejayoharen]

Yes, I did that. IIRC, I also got a different mysterious error until I added that.

It is possible I'm using some other unsupported annotations.

[mevivs]

Ok. Let me know, if you can carve out a sample example to verify and look into the issue.

-Vivek

[bejayoharen]

Is @MappedSuperclass supported?

[mevivs]

Not yet.
#56

[bejayoharen]

Thanks. That may be my issue. I can't tell with current error messages.