Endless MongoDB ReplicaSetStatus updater exceptions using the Java driver in Spring

Question

I just deployed a Spring web application onto Glassfish. This app contains an injected Spring bean for the Mongo object, which is pretty basic, it just looks like this:

<bean id="mongo" class="com.mongodb.Mongo">
    <constructor-arg value="127.0.0.1" />
    <constructor-arg value="27017" />
</bean>

I fire up my web app, then use this Mongo object to query the db and insert records and whatnot.. and everything works fine.

But in my server.log file I get and endless stream of SEVERE error messages. They are NullPointerExceptions and IOExceptions. They appear to have something to do with ReplicaSetStatus, but I don't know why it keeps trying to connect, is it turn on be default?

Does anyone know what causes these? How can I fix the problem, or stop whatever is causing them?

// EDIT: The exceptions start immediately after I deploy my application. But they do not stop when I disable my application, or even undeploy it.

These messages just get written constantly, but from what I can see theres only 4 types of errors:

[#|2011-04-22T17:49:40.818+0900|SEVERE|glassfish3.1|com.mongodb.ReplicaSetStatus|_ThreadID=37;_ThreadName=Thread-1;|can't update node: 27017:27017
java.lang.NullPointerException
    at com.mongodb.OutMessage.reset(OutMessage.java:73)
    at com.mongodb.OutMessage.<init>(OutMessage.java:51)
    at com.mongodb.OutMessage.query(OutMessage.java:38)
    at com.mongodb.DBPort.findOne(DBPort.java:127)
    at com.mongodb.DBPort.runCommand(DBPort.java:138)
    at com.mongodb.ReplicaSetStatus$Node.update(ReplicaSetStatus.java:149)
    at com.mongodb..updateAll(ReplicaSetStatus.java:314)
    at com.mongodb.ReplicaSetStatus$Updater.run(ReplicaSetStatus.java:263)
|#]

[#|2011-04-22T17:49:40.818+0900|SEVERE|glassfish3.1|com.mongodb.ReplicaSetStatus|_ThreadID=37;_ThreadName=Thread-1;|can't update node: localhost:27017
java.lang.NullPointerException
    at com.mongodb.OutMessage.reset(OutMessage.java:73)
    at com.mongodb.OutMessage.<init>(OutMessage.java:51)
    at com.mongodb.OutMessage.query(OutMessage.java:38)
    at com.mongodb.DBPort.findOne(DBPort.java:127)
    at com.mongodb.DBPort.runCommand(DBPort.java:138)
    at com.mongodb.ReplicaSetStatus$Node.update(ReplicaSetStatus.java:149)
    at com.mongodb.ReplicaSetStatus.updateAll(ReplicaSetStatus.java:314)
    at com.mongodb.ReplicaSetStatus.ensureMaster(ReplicaSetStatus.java:306)
    at com.mongodb.DBTCPConnector.checkMaster(DBTCPConnector.java:383)
    at com.mongodb.ReplicaSetStatus$Updater.run(ReplicaSetStatus.java:275)
|#]

[#|2011-04-22T17:49:41.676+0900|SEVERE|glassfish3.1|com.mongodb.ReplicaSetStatus|_ThreadID=48;_ThreadName=Thread-1;|can't update node: 127.0.0.1:27017
java.io.IOException: couldn't connect to [/127.0.0.1:27017] bc:java.net.ConnectException: Connection refused: connect
    at com.mongodb.DBPort._open(DBPort.java:206)
    at com.mongodb.DBPort.go(DBPort.java:94)
    at com.mongodb.DBPort.go(DBPort.java:75)
    at com.mongodb.DBPort.findOne(DBPort.java:129)
    at com.mongodb.DBPort.runCommand(DBPort.java:138)
    at com.mongodb.ReplicaSetStatus$Node.update(ReplicaSetStatus.java:149)
    at com.mongodb.ReplicaSetStatus.updateAll(ReplicaSetStatus.java:314)
    at com.mongodb.ReplicaSetStatus.ensureMaster(ReplicaSetStatus.java:306)
    at com.mongodb.DBTCPConnector.checkMaster(DBTCPConnector.java:383)
    at com.mongodb.ReplicaSetStatus$Updater.run(ReplicaSetStatus.java:275)
|#]

[#|2011-04-22T17:49:41.676+0900|SEVERE|glassfish3.1|com.mongodb.ReplicaSetStatus|_ThreadID=48;_ThreadName=Thread-1;|can't update node: 27017:27017
java.io.IOException: couldn't connect to [/0.0.105.137:27017] bc:java.net.SocketException: Network is unreachable: connect
    at com.mongodb.DBPort._open(DBPort.java:206)
    at com.mongodb.DBPort.go(DBPort.java:94)
    at com.mongodb.DBPort.go(DBPort.java:75)
    at com.mongodb.DBPort.findOne(DBPort.java:129)
    at com.mongodb.DBPort.runCommand(DBPort.java:138)
    at com.mongodb.ReplicaSetStatus$Node.update(ReplicaSetStatus.java:149)
    at com.mongodb.ReplicaSetStatus.updateAll(ReplicaSetStatus.java:314)
    at com.mongodb.ReplicaSetStatus.ensureMaster(ReplicaSetStatus.java:306)
    at com.mongodb.DBTCPConnector.checkMaster(DBTCPConnector.java:383)
    at com.mongodb.ReplicaSetStatus$Updater.run(ReplicaSetStatus.java:275)
|#]

Answer 1

Change your Mongo bean definition in Spring context file as here:

    <constructor-arg value="${db.host}" type="java.lang.String" />
    <constructor-arg value="${db.port}" type="int" />

If you omit type attributes, another Mongo class constructor is invoked, where arguments are instances of com.mongodb.ServerAddress type, and 27017 is treated as a hostname and InetAddress.getAllByName( host ) resolves to this IP 0.0.105.137.