使用 JUnitCore 时出现 java.lang.NoClassDefFoundError

Question

Exception in thread "main" java.lang.NoClassDefFoundError: 
org/junit/runner/JUnitCore
    at springbook.learningtest.junit.JUnitTest.main(JUnitTest.java:7)
Caused by: java.lang.ClassNotFoundException: org.junit.runner.JUnitCore
    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)
    ... 1 more

I found similar error in java.lang.NoClassDefFoundError in junit . But I already added junit to my project with maven . Then, I checked Maven Dependencies and found there was junit-4.12.jar. I tried some different version of junit and spring , but all my attempts were failed. Below I attached My codes.

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <groupId>TobySpring3.1</groupId>
    <artifactId>TobySpring3.1</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <build>
        <sourceDirectory>src</sourceDirectory>
        <plugins>
            <plugin>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>3.6.1</version>
                <configuration>
                    <source />
                    <target />
                </configuration>
            </plugin>
        </plugins>
    </build>
    <dependencies>
        <!-- MySQL -->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.45</version>
        </dependency>
        <!-- Spring -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-context</artifactId>
            <version>3.1.4.RELEASE</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-instrument</artifactId>
            <version>3.1.4.RELEASE</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-jdbc</artifactId>
            <version>3.1.4.RELEASE</version>
        </dependency>
        <!-- JUNIT -->
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.12</version>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>org.hamcrest</groupId>
            <artifactId>hamcrest-library</artifactId>
            <version>1.3</version>
            <scope>test</scope>
        </dependency>
        <!-- CGLIB -->
        <dependency>
            <groupId>cglib</groupId>
            <artifactId>cglib</artifactId>
            <version>2.2.2</version>
        </dependency>
    </dependencies>
</project>

Above is my pom.xml

package springbook.learningtest.junit;

import org.junit.runner.JUnitCore;

public class JUnitTest {
    public static void main(String[] args) {
        JUnitCore.main("springbook.user.test.UserDaoTest");
    }
}

.

package springbook.user.test;

import static org.hamcrest.CoreMatchers.is;
import static org.junit.Assert.assertThat;

import java.sql.SQLException;

import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.GenericXmlApplicationContext;

import springbook.user.dao.UserDao;
import springbook.user.domain.User;

public class UserDaoTest {

    @Test
    public void addAndGet() throws ClassNotFoundException, SQLException {
        ApplicationContext context = new GenericXmlApplicationContext("applicationContext.xml");
        UserDao dao = context.getBean("userDao", UserDao.class);

        User user = new User();
        user.setId("gyumee");
        user.setName("name");
        user.setPassword("password");

        dao.add(user);

        User user2 = dao.get(user.getId());

        assertThat(user2.getName(), is(user.getName()));
        assertThat(user2.getPassword(), is(user.getPassword()));
    }
}

Answer 1

Surprisingly i was also facing same error log, adding these hamcrest-core solved the issue in my case.

<!-- https://mvnrepository.com/artifact/org.hamcrest/hamcrest-core -->
<dependency>
    <groupId>org.hamcrest</groupId>
    <artifactId>hamcrest-core</artifactId>
    <version>1.3</version>
    <scope>test</scope>
</dependency>

from Here .

Answer 2

When I changed junit to 4.7 with maven, it stil didn't work. I checked Maven Dependencies and there was junit-4.7.jar . Still same error messeage. I added junit-4.7.jar in Java Build Path again (See below image)

Then, it worked well! But, still I don't know why this problem happened ;( . Does anyone know why?

Answer 3

I am even getting the same error as Exception in thread "main" java.lang.NoClassDefFoundError: org/junit/runner/JUnitCore

What I am basically trying here is to run the JUnit tests directly calling the executable jar file (of my application). When I run the application in my local it works expected and main is called along with test execution happens

public static void main( String[] args )
    {
        System.out.println( "Hello World!" );
        System.out.println("Starting Integration Tests!");
        JUnitCore engine = new JUnitCore();
        engine.run(test.class);
    }

This calls the test class and runs all the desired tests but then when I try to execute the jar from the command line as below it fails C:\\Users\\tripate\\eclipse\\testing\\target>java -jar testing-0.0.1-SNAPSHOT.jar Hello World! Starting Integration Tests!

    Exception in thread "main" java.lang.NoClassDefFoundError: org/junit/runner/JUnitCore
        at MVP2.testing.App.main(App.java:15)
Caused by: java.lang.ClassNotFoundException: org.junit.runner.JUnitCore
        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)

Note: The jar is generated as the part of maven build here. I have both JUnit and hamcrest dependency in my POM file

Answer 4

you are running the test classes through test suite which run as java application not as test. In pom for junit dependency remove scope "test" , as scope is defined as test that's why test suite not able to find JUnit class.

 <dependency>
          <groupId>junit</groupId>
          <artifactId>junit</artifactId>
          <version>4.12</version>
    </dependency>