How to avoid dependency conflict when using dropwizard + jersey client

Question

I have a DropWizard REST API written and works. One of the resource endpoints actually writes an email, however as soon as I add the following dependencies DropWizard starts to fail on start up

<dependency>
        <groupId>com.sun.jersey</groupId>
        <artifactId>jersey-client</artifactId>
        <version>1.18.1</version>
    </dependency>
    <dependency>
        <groupId>com.sun.jersey</groupId>
        <artifactId>jersey-core</artifactId>
        <version>1.18.1</version>
    </dependency>
    <dependency>
        <groupId>com.sun.jersey.contribs</groupId>
        <artifactId>jersey-multipart</artifactId>
        <version>1.18.1</version>
    </dependency>

The DropWizard dependency is:

<dependency>
        <groupId>io.dropwizard</groupId>
        <artifactId>dropwizard-core</artifactId>
        <version>0.8.1</version>
    </dependency>

The error on startup is really long, summarised below

    WARN  [2015-05-01 20:06:08,887] org.glassfish.jersey.internal.Errors: The following warnings have been detected: WARNING: Unknown HK2 failure detected:
MultiException stack 1 of 2
java.lang.NullPointerException
    at com.sun.jersey.core.provider.jaxb.AbstractJAXBProvider.setConfiguration(AbstractJAXBProvider.java:113)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:606)
    ....
    MultiException stack 2 of 2
java.lang.IllegalStateException: Unable to perform operation: method inject on com.sun.jersey.core.impl.provider.entity.XMLRootElementProvider$App
    at org.jvnet.hk2.internal.ClazzCreator.create(ClazzCreator.java:395)
    ....
    MultiException stack 3 of 3
java.lang.IllegalStateException: Unable to perform operation: create on org.glassfish.jersey.message.internal.MessageBodyFactory
    ...

I'm guessing DropWizard is using another conflicting dependency so how do I deal with this?

Thanks in advance

Answer 1

Dropwizard 0.8.x uses Jersey 2.x which naturally conflicts with your Jersey 1.x dependencies.

I think it might be fine with jersey-client as long as you don't have dropwizard-client dependency but jersey-core will conflict at many points with dropwizard's jersey which I don't think you can fix. And also I don't think you'd need jersey-core for sending email anyway.

If you do need jersey for this, try using Jersey 2.16 instead which is the version dropwizard is using.