How to fix class “javax.servlet.FilterRegistration”‘s signer information does not match signer information of other classes in the same package (when unit testing with Spark Streaming)

I’ve recently started to write some unit tests for a Spark Streaming application and even the simplest scenario led to the following error:

class “javax.servlet.FilterRegistration”‘s signer information does not match signer information of other classes in the same package

This happened when Maven ran the test, in other words, it was a run-time error. An Internet search indicated that I should be suspicious about different versions of javax.servlet. The following commands showed that I was on the right track:

mvn dependency:tree

mvn dependency:tree | grep servlet

Modifying the pom.xml for excluding javax.servlet as follows solved the problem:

<dependency>
  <groupId>org.apache.hadoop</groupId>
  <artifactId>hadoop-common</artifactId>
  <version>2.4.0</version>
  <scope>provided</scope>
  <exclusions>
    <exclusion>
      <groupId>javax.servlet</groupId>
      <artifactId>*</artifactId>
      </exclusion>
   </exclusions>
 </dependency>

I hope things will be less conflicting in the upcoming Hadoop and Spark versions.

About the author: Emre is the co-founder & CTO of TM Data ICT Solutions in Belgium. You can read more about him in About page of this blog.