ScalaTest - java.lang.IncompatibleClassChangeError: Implementing class

Question

I'm getting IncompatibleClassChangeError when run test as ScalaTest from eclipse, the flowing is the full stack trace of the errors. Can anyone give me some advise? Thanks in advance!

An exception or error caused a run to abort. This may have been caused by a problematic custom reporter.
    java.lang.IncompatibleClassChangeError: Implementing class
        at java.lang.ClassLoader.defineClass1(Native Method)
        at java.lang.ClassLoader.defineClass(Unknown Source)
        at java.security.SecureClassLoader.defineClass(Unknown Source)
        at java.net.URLClassLoader.defineClass(Unknown Source)
        at java.net.URLClassLoader.access$100(Unknown Source)
        at java.net.URLClassLoader$1.run(Unknown Source)
        at java.net.URLClassLoader$1.run(Unknown Source)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.net.URLClassLoader.findClass(Unknown Source)
        at java.lang.ClassLoader.loadClass(Unknown Source)
        at java.lang.ClassLoader.loadClass(Unknown Source)
        at java.lang.ClassLoader.defineClass1(Native Method)
        at java.lang.ClassLoader.defineClass(Unknown Source)
        at java.security.SecureClassLoader.defineClass(Unknown Source)
        at java.net.URLClassLoader.defineClass(Unknown Source)
        at java.net.URLClassLoader.access$100(Unknown Source)
        at java.net.URLClassLoader$1.run(Unknown Source)
        at java.net.URLClassLoader$1.run(Unknown Source)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.net.URLClassLoader.findClass(Unknown Source)
        at java.lang.ClassLoader.loadClass(Unknown Source)
        at java.lang.ClassLoader.loadClass(Unknown Source)
        at java.lang.ClassLoader.loadClass(Unknown Source)
        at org.scalatest.tools.Runner$$anonfun$35.apply(Runner.scala:2438)
        at org.scalatest.tools.Runner$$anonfun$35.apply(Runner.scala:2436)
        at scala.collection.TraversableLike$$anonfun$filter$1.apply(TraversableLike.scala:264)
        at scala.collection.immutable.List.foreach(List.scala:318)
        at scala.collection.TraversableLike$class.filter(TraversableLike.scala:263)
        at scala.collection.AbstractTraversable.filter(Traversable.scala:105)
        at org.scalatest.tools.Runner$.doRunRunRunDaDoRunRun(Runner.scala:2436)
        at org.scalatest.tools.Runner$$anonfun$runOptionallyWithPassFailReporter$2.apply(Runner.scala:1044)
        at org.scalatest.tools.Runner$$anonfun$runOptionallyWithPassFailReporter$2.apply(Runner.scala:1043)
        at org.scalatest.tools.Runner$.withClassLoaderAndDispatchReporter(Runner.scala:2722)
        at org.scalatest.tools.Runner$.runOptionallyWithPassFailReporter(Runner.scala:1043)
        at org.scalatest.tools.Runner$.main(Runner.scala:860)
        at org.scalatest.tools.Runner.main(Runner.scala)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
        at java.lang.reflect.Method.invoke(Unknown Source)
        at scala.tools.eclipse.scalatest.launching.ScalaTestLauncher$.main(ScalaTestLauncher.scala:20)
        at scala.tools.eclipse.scalatest.launching.ScalaTestLauncher.main(ScalaTestLauncher.scala)

Jar dependency and maven plugins are like below:

<build>
    <pluginManagement>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-resources-plugin</artifactId>
                <version>2.6</version>
            </plugin>
            <plugin>
                <groupId>org.codehaus.mojo</groupId>
                <artifactId>build-helper-maven-plugin</artifactId>
                <version>1.8</version>
            </plugin>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-clean-plugin</artifactId>
                <version>2.5</version>
            </plugin>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-deploy-plugin</artifactId>
                <version>2.7</version>
            </plugin>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-install-plugin</artifactId>
                <version>2.4</version>
            </plugin>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-project-info-reports-plugin</artifactId>
                <version>2.6</version>
            </plugin>
        </plugins>
    </pluginManagement>

    <plugins>
        <plugin>
            <groupId>net.alchim31.maven</groupId>
            <artifactId>scala-maven-plugin</artifactId>
            <version>3.2.0</version>
            <executions>
                <execution>
                    <goals>
                        <goal>compile</goal>
                        <goal>testCompile</goal>
                    </goals>
                </execution>
            </executions>
        </plugin>
        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-compiler-plugin</artifactId>
            <version>3.1</version>
            <configuration>
                <source>1.7</source>
                <target>1.7</target>
                <showWarnings>true</showWarnings>
            </configuration>
        </plugin>
        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-jar-plugin</artifactId>
            <version>2.4</version>
        </plugin>
    </plugins>
</build>

<dependencies>
    <dependency>
        <groupId>org.scala-lang</groupId>
        <artifactId>scala-library</artifactId>
        <version>2.10.5</version>
    </dependency>
    <dependency>
        <groupId>org.scalatest</groupId>
        <artifactId>scalatest_2.10</artifactId>
        <version>2.2.4</version>
        <scope>test</scope>
    </dependency>
    <dependency>
        <groupId>junit</groupId>
        <artifactId>junit</artifactId>
        <version>4.12</version>
    </dependency>
</dependencies>

Answer 1

I was having a similar problem. The issue was that the test class had the same name as the tested file, and was in the same package. If that's your case, a simple rename would be enough.

Hope it helps someone!