POJO mapping - Setter can't be found if property is capitalized like xAxis

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    • Type: Improvement
    • Resolution: Unresolved
    • Priority: Minor - P4
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    • Affects Version/s: None
    • Component/s: POJO
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      A user reached out to me because his piece of code wasn't working as expected.

      https://gist.github.com/pavangayakwad/5adbece8e11b26508a1338dc032c60ae 

      He had a POJO with a few fields and 2 of them were named "xAxisColumn" and "yAxisColumn".

      All the fields were mapped correctly - he could write them to MDB but not retrieve these 2. 

      His IDE and mine (IntelliJ) generated the getter and setter like so: 

      getxAxisColumn and setxAxisColumn (note the lower case X).

      And we are expecting getXAxisColumn (upper case X) apparently which respect the CamelCase - but apparently this is not the correct answer as it's not respecting the JavaBeans API specification from 1997

      This isn't a big deal per say - and there is an easy workaround. But this is really confusing and not an easy bug to find / understand as it's based on introspection if I understand this correctly.

      Here is a piece of code to illustrate better what I'm saying.

      import com.mongodb.ConnectionString;
import com.mongodb.MongoClientSettings;
import com.mongodb.client.MongoClient;
import com.mongodb.client.MongoClients;
import com.mongodb.client.MongoCollection;
import com.mongodb.client.MongoDatabase;
import org.bson.codecs.configuration.CodecRegistry;
import org.bson.codecs.pojo.PojoCodecProvider;

import static org.bson.codecs.configuration.CodecRegistries.fromProviders;
import static org.bson.codecs.configuration.CodecRegistries.fromRegistries;

public class MappingPOJOFailed {

    public static void main(String[] args) {
        ConnectionString connectionString = new ConnectionString("mongodb://localhost");
        CodecRegistry pojoCodecRegistry = fromProviders(PojoCodecProvider.builder().register(Good.class, Bad.class).build());
        CodecRegistry codecRegistry = fromRegistries(MongoClientSettings.getDefaultCodecRegistry(), pojoCodecRegistry);
        MongoClientSettings clientSettings = MongoClientSettings.builder()
                                                                .applyConnectionString(connectionString)
                                                                .codecRegistry(codecRegistry)
                                                                .build();
        try (MongoClient mongoClient = MongoClients.create(clientSettings)) {
            MongoDatabase db = mongoClient.getDatabase("test");
            MongoCollection<Good> goodColl = db.getCollection("good", Good.class);
            MongoCollection<Bad> badcoll = db.getCollection("bad", Bad.class);

            goodColl.insertOne(new Good().setXAxis("I'm here!"));
            System.out.println(goodColl.find().first().getXAxis()); // This line prints "I'm here!"

            badcoll.insertOne(new Bad().setxAxis("I'm NOT here!"));
            System.out.println(badcoll.find().first().getxAxis()); // This line SHOULD print "I'm NOT here!" but I get "null".
            goodColl.drop();
            badcoll.drop();
        }
    }

    public static class Good {
        private String xAxis;

        public String getXAxis() {
            return xAxis;
        }

        public Good setXAxis(String xAxis) {
            this.xAxis = xAxis;
            return this;
        }
    }

    public static class Bad {
        private String xAxis;

        public String getxAxis() {
            return xAxis;
        }

        public Bad setxAxis(String xAxis) {
            this.xAxis = xAxis;
            return this;
        }
    }
}

      Ouput:

      I'm here!
null

            Assignee:
            Unassigned
            Reporter:
            Maxime Beugnet (Inactive)
            None
            Votes:
            0 Vote for this issue
            Watchers:
            3 Start watching this issue

              Created:
              Updated: