java.lang.NoClassDefFoundError: org/hamcrest/SelfDescribing

问题

While running junit test in eclipse I am getting this Exception:

java.lang.NoClassDefFoundError: org/hamcrest/SelfDescribing

I\'ve added junit.jar library file.

I\'ve tried different versions of junit.jar: 4.4, 4.8, etc.

How do I fix this Exception?

回答1:

Add hamcrest-all-X.X.jar to your classpath.

Latest version as of Feb 2015 is 1.3: http://code.google.com/p/hamcrest/downloads/detail?name=hamcrest-all-1.3.jar&can=2&q=

回答2:

According to the JUnit GitHub team website (https://github.com/junit-team/junit/wiki/Download-and-Install), junit.jar and hamcrest-core.jar are both needed in the classpath when using JUnit 4.11.

Here is the Maven dependency block for including junit and hamcrest.

<dependency>
    <groupId>junit</groupId>
    <artifactId>junit</artifactId>
    <version>4.1.2</version>
    <scope>test</scope>
</dependency>
<!-- Needed by junit -->
<dependency>
    <groupId>org.hamcrest</groupId>
    <artifactId>hamcrest-all</artifactId>
    <version>1.3</version>
    <scope>test</scope>
</dependency>

回答3:

A few steps you have to follow:

Right click on the project.
Choose Build Path Then from its menu choose Add Libraries.
Choose JUnit then click Next.
Choose JUnit4 then Finish.

回答4:

Works for me: IntelliJ IDEA 13.1.1, JUnit4, Java 6

I changed the file in project path: [PROJECT_NAME].iml

Replaced:

  <library>
    <CLASSES>
      <root url="jar://$APPLICATION_HOME_DIR$/lib/junit-4.11.jar!/" />
    </CLASSES>
    <JAVADOC />
    <SOURCES />
  </library>

By:

  <library name="JUnit4">
    <CLASSES>
      <root url="jar://$APPLICATION_HOME_DIR$/lib/junit-4.11.jar!/" />
      <root url="jar://$APPLICATION_HOME_DIR$/lib/hamcrest-core-1.3.jar!/" />
      <root url="jar://$APPLICATION_HOME_DIR$/lib/hamcrest-library-1.3.jar!/" />
    </CLASSES>
    <JAVADOC />
    <SOURCES />
  </library>

So the final .iml file is:

<?xml version="1.0" encoding="UTF-8"?>
<module type="JAVA_MODULE" version="4">
  <component name="NewModuleRootManager" inherit-compiler-output="true">
    <exclude-output />
    <content url="file://$MODULE_DIR$">
      <sourceFolder url="file://$MODULE_DIR$/src" isTestSource="false" />
      <sourceFolder url="file://$MODULE_DIR$/tests" isTestSource="true" />
    </content>
    <orderEntry type="inheritedJdk" />
    <orderEntry type="sourceFolder" forTests="false" />
    <orderEntry type="module-library">
      <library name="JUnit4">
        <CLASSES>
          <root url="jar://$APPLICATION_HOME_DIR$/lib/junit-4.11.jar!/" />
          <root url="jar://$APPLICATION_HOME_DIR$/lib/hamcrest-core-1.3.jar!/" />
          <root url="jar://$APPLICATION_HOME_DIR$/lib/hamcrest-library-1.3.jar!/" />
        </CLASSES>
        <JAVADOC />
        <SOURCES />
      </library>
    </orderEntry>
  </component>
</module>

P.S.: save the file and don't let to IntelliJ Idea reload it. Just once.

回答5:

You need junit-dep.jar because the junit.jar has a copy of old Hamcrest classes.

回答6:

This problem is because of your classpath miss hamcrest-core-1.3.jar. To resolve this add hamcrest-core-1.3.jar as you add junit-4.XX.jar into your classpath.

At first, I encounter this problem too, but after I refer to the official site and add hamcrest-core-1.3.jar into classpath with command line, it works properly finally.

javac -d ../../../../bin/ -cp ~/libs/junit-4.12.jar:/home/limxtop/projects/algorithms/bin  MaxHeapTest.java 

java -cp ../../../../bin/:/home/limxtop/libs/junit-4.12.jar:/home/limxtop/libs/hamcrest-core-1.3.jar org.junit.runner.JUnitCore com.limxtop.heap.MaxHeapTest

回答7:

As a general rule, always make sure hamcrest is before any other testing libraries on the classpath, as many such libraries include hamcrest classes and may therefore conflict with the hamcrest version you're using. This will resolve most problems of the type you're describing.

回答8:

Just in case there's anyone here using netbeans and has the same problem, all you have to do is

Right click on TestLibraries
Click on Add Library
Select JUnit and click add library
Repeat the process but this time click on Hamcrest and the click add library

This should solve the problem

回答9:

You need to add the hamcrest-core JAR to the classpath as described here: https://github.com/junit-team/junit4/wiki/Download-and-Install

回答10:

It sounds like a classpath issue, so there are a few different ways to go about it. Where does org/hamcret/SelfDescribing come from? Is that your class or in a different jar?

Try going to your project Build Path and on the Libraries tab, add a Library. You should be able to choose JUnit to your project. This is a little bit different than just having the JUnit jar file In your project.

In your Run Configuration for the JUnit test, check the Classpath. You could probably fix this by adding making sure your Classpath can see that SelfDescribing class there. The Run option in Eclipse has a different set of options for the JUnit options.

回答11:

If this problem arise in a RCP project it can be because JUnit has been explicitly imported.

Check the editor for your plugin.xml under Dependencies tab, remove the org.junit from the Imported Packages and add org.junit to the Required Plug-ins.

回答12:

The problem is when you set up eclipse to point to JRE instead of JDK. JRE has junit4.jar in the lib/ext folder, but not hamcrest.jar :) So the solution is to check installed JREs in Eclipse, remove the existing one and create a new one pointing to your JDK.

回答13:

the simplest way of solving the problem to begin with is copying latest version of hamcrest-code.jar into your CLASSPATH that is the file you store other .jar files needed for compilation and running of your application.

that could be e.g.: C:/ant/lib

回答14:

This happens when you run Ant via command line. The implicit user dependencies are added in the classpath at the end and take precedence over the project-added classpath. Run Ant with -nouserlib flag. The implicit dependencies would be excluded from the classpath.

回答15:

I had the same problem, the solution is to add in build path/plugin the jar org.hamcrest.core_1xx, you can find it in eclipse/plugins.

回答16:

There is a better answer to solve this problem. add dependency

<dependency>
    <groupId>org.hamcrest</groupId>
    <artifactId>hamcrest-all</artifactId>
    <version>1.3</version>
    <scope>test</scope>
</dependency>