运行 Junit 测试时出现错误 NoClassDefFoundError

Question

When I run this script to automate:

 package testRunners; import org.junit.runner.RunWith; import io.cucumber.junit.Cucumber; import io.cucumber.junit.CucumberOptions; @RunWith(Cucumber.class) @CucumberOptions(features="resources/features", glue="") public class TestRunner_GoogleHomepage { }

I use:

• cucumber-core-5.7.0.jar
• cucumber-java-5.7.0.jar
• cucumber-junit-5.7.0.jar
• cucumber-jvm-deps-1.0.6.jar
• gherkin-8.2.1.jar
• junit-4.12.jar
• mockito-all-1.10.19.jar

I obtain this error result in Java track trace console:

java.lang.NoClassDefFoundError: io/cucumber/plugin/event/EventPublisher
    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$1.run(Unknown Source)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.net.URLClassLoader.findClass(Unknown Source)
    at java.lang.ClassLoader.loadClass(Unknown Source)
    at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
    at java.lang.ClassLoader.loadClass(Unknown Source)
    at java.lang.Class.getDeclaredConstructors0(Native Method)
    at java.lang.Class.privateGetDeclaredConstructors(Unknown Source)
    at java.lang.Class.getConstructor0(Unknown Source)
    at java.lang.Class.getConstructor(Unknown Source)
    at org.junit.internal.builders.AnnotatedBuilder.buildRunner(AnnotatedBuilder.java:104)
    at org.junit.internal.builders.AnnotatedBuilder.runnerForClass(AnnotatedBuilder.java:86)
    at org.junit.runners.model.RunnerBuilder.safeRunnerForClass(RunnerBuilder.java:59)
    at org.junit.internal.builders.AllDefaultPossibilitiesBuilder.runnerForClass(AllDefaultPossibilitiesBuilder.java:26)
    at org.junit.runners.model.RunnerBuilder.safeRunnerForClass(RunnerBuilder.java:59)
    at org.junit.internal.requests.ClassRequest.getRunner(ClassRequest.java:33)
    at org.eclipse.jdt.internal.junit4.runner.JUnit4TestLoader.createUnfilteredTest(JUnit4TestLoader.java:90)
    at org.eclipse.jdt.internal.junit4.runner.JUnit4TestLoader.createTest(JUnit4TestLoader.java:76)
    at org.eclipse.jdt.internal.junit4.runner.JUnit4TestLoader.loadTests(JUnit4TestLoader.java:49)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:526)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:770)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:464)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:210)
Caused by: java.lang.ClassNotFoundException: io.cucumber.plugin.event.EventPublisher
    at java.net.URLClassLoader.findClass(Unknown Source)
    at java.lang.ClassLoader.loadClass(Unknown Source)
    at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
    at java.lang.ClassLoader.loadClass(Unknown Source)
    ... 29 morec

Answer 1

I use:

 cucumber-core-5.7.0.jar cucumber-java-5.7.0.jar cucumber-junit-5.7.0.jar cucumber-jvm-deps-1.0.6.jar gherkin-8.2.1.jar junit-4.12.jar

It would appear that you are manually downloading jar files. This is not a practice I would recommend. If you follow the 10 minute tutorial you'll get an introduction that uses Maven dependency management.

In addition to this tutorial I would strongly urge you to invest time in learning either Maven or Gradle along with Cucumber. Amongst other things these tools will automate your dependency management and this can make your life much easier.

For example:

If you want to use Cucumber with JUnit 4 and annotation based step definitions you would declare this minimal set of dependencies in a Maven pom.xml file.

    <properties>
        <cucumber.version>5.7.0</cucumber.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>io.cucumber</groupId>
            <artifactId>cucumber-java</artifactId>
            <version>${cucumber.version}</version>
            <scope>test</scope>
        </dependency>

        <dependency>
            <groupId>io.cucumber</groupId>
            <artifactId>cucumber-junit</artifactId>
            <version>${cucumber.version}</version>
            <scope>test</scope>
        </dependency>
    </dependencies>

By telling Maven what your dependencies are Maven can calculate your transitive dependencies ie: the dependencies of your dependencies.

This has many advantages. One example would be using the mvn dependency:tree command to list all dependencies. This is much faster and much less error prone then downloading jar files by hand and hoping that you have the right ones.

$ mvn dependency:tree
[INFO] Scanning for projects...
[INFO] 
[INFO] ------------------< cucumber:cucumber-java-skeleton >-------------------
[INFO] Building Cucumber-Java Skeleton 0.0.1
[INFO] --------------------------------[ jar ]---------------------------------
[INFO] 
[INFO] --- maven-dependency-plugin:2.8:tree (default-cli) @ cucumber-java-skeleton ---
[INFO] cucumber:cucumber-java-skeleton:jar:0.0.1
[INFO] +- io.cucumber:cucumber-java:jar:5.7.0:test
[INFO] |  +- io.cucumber:cucumber-core:jar:5.7.0:test
[INFO] |  |  +- io.cucumber:cucumber-gherkin:jar:5.7.0:test
[INFO] |  |  +- io.cucumber:cucumber-gherkin-vintage:jar:5.7.0:test
[INFO] |  |  +- io.cucumber:tag-expressions:jar:2.0.4:test
[INFO] |  |  +- io.cucumber:cucumber-expressions:jar:8.3.1:test
[INFO] |  |  +- io.cucumber:datatable:jar:3.3.0:test
[INFO] |  |  +- io.cucumber:cucumber-plugin:jar:5.7.0:test
[INFO] |  |  \- io.cucumber:docstring:jar:5.7.0:test
[INFO] |  \- org.apiguardian:apiguardian-api:jar:1.1.0:test
[INFO] +- io.cucumber:cucumber-junit:jar:5.7.0:test
[INFO] \- junit:junit:jar:4.13:test
[INFO]    \- org.hamcrest:hamcrest-core:jar:1.3:test
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time:  0.781 s
[INFO] Finished at: 2020-02-10T23:00:14+01:00
[INFO] ------------------------------------------------------------------------

Answer 2

I believe that below dependency is missing. Could you please add the below dependency in your project. Version must be same as the other cucumber dependencies.

<dependency>
    <groupId>io.cucumber</groupId>
    <artifactId>cucumber-plugin</artifactId>
    <version>5.7.0</version>
</dependency>