[Java] MongoClient via JNDI - ClassCastException

[Jens Heider]

I've tried to inject the MongoClient via JNDI into my Java class like described here: http://mongodb.github.io/mongo-java-driver/3.3/driver/reference/connecting/jndi/

@Resource(name = "java:global/MongoClient")
private MongoClient mongoClient;

Unfortunately,  i'm getting a

java.lang.IllegalArgumentException: Can not set com.mongodb.MongoClient field [...] to com.mongodb.MongoClient

For me the classes seems to be identically. I'm using the same mongodb java driver version in wildfly module as well as in my application.
When changing the field to be just an `Object`, the injection is working, but then I'm getting a

java.lang.ClassCastException: com.mongodb.MongoClient cannot be cast to com.mongodb.MongoClient

Could anybody give me a hint, what might be the problem?

Thanks in advance :)

[Abhijit Das]

Hi Jens,

Did u managed to solve this issue?

Thanks in advance.

[Jeff Yemin]

This look like a classpath issue.  If com.mongodb.MongoClient can't be cast to com.mongodb.MongoClient then there there must be two instances of that class in two different class loaders. The JVM spec requires that those are treated as different classes.

One way to debug this is to enable verbose class loading (java -verbose:class) and determine where MongoClient is being loaded from.  Then make sure the driver jar file is only available from one location.

Regards,

Jeff

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[Quentin Tirroloni]

Thanks a lot for your clues !!!
I had the same issue

java.lang.IllegalArgumentException: Can not set com.mongodb.MongoClient field [...] to com.mongodb.MongoClient

I was using MongoDB Driver (The driver includes a JNDI ObjectFactory implementation, MongoClientFactory, that returns MongoClient instances based on a connection string.)
http://mongodb.github.io/mongo-java-driver/3.3/driver/reference/connecting/jndi/

My problem was that I didn't used in a good way the module...


In my ear pom.xml we have to add the module in the manifest entry

<plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-ear-plugin</artifactId>
                <configuration>
                    <filtering>true</filtering>
                    <filters />
                    <archive>
                        <manifestEntries>
                                <Dependencies>org.mongodb,org.slf4j</Dependencies>
                        </manifestEntries>
                    </archive>
                </configuration>
</plugin>

Then in the Java Code, we have to use the following annotation

@Resource(name = "java:global/MongoClient")
private MongoClient mongoClient;

Quentin