java.lang.noclassdeffounderror for Maven

Question

I am new at Maven and I recently created this program that requires multivaluedmap. Since I did not have jsr311-api.jar, I downloaded it from online, but I have no clue where to place them. I decided to upload it onto the apache-maven/lib folder and tried to run the program, but it did not work. This is the error that I get.

Exception in thread "main" java.lang.NoClassDefFoundError: javax/ws/rs/core/Mul
ivaluedMap
    at java.lang.Class.getDeclaredMethods0(Native Method)
    at java.lang.Class.privateGetDeclaredMethods(Unknown Source)
    at java.lang.Class.privateGetMethodRecursive(Unknown Source)
    at java.lang.Class.getMethod0(Unknown Source)
    at java.lang.Class.getMethod(Unknown Source)
    at sun.launcher.LauncherHelper.validateMainClass(Unknown Source)
    at sun.launcher.LauncherHelper.checkAndLoadMain(Unknown Source)
Caused by: java.lang.ClassNotFoundException: javax.ws.rs.core.MultivaluedMap
    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)
    ... 7 more

I assumed that I'm getting errors from misplacing the .jar file. Thank you in advance for your help.

This is my pom file that I currently have: http://maven.apache.org/xsd/maven-4.0.0.xsd"> 4.0.0

<groupId>com.test.api</groupId>
<artifactId>testing</artifactId>
<packaging>jar</packaging>
<version>0.1.0</version>
<name>testPlatform</name>

<properties>
    <source.version>1.7</source.version>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
</properties>

<build>
    <plugins>

        <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>
            </configuration>
        </plugin>

    </plugins>
</build>

<dependencies>
    <dependency>
  <groupId>junit</groupId>
  <artifactId>junit</artifactId>
  <version>3.8.1</version>
  <scope>test</scope>
</dependency>
    <!-- REST client -->
    <dependency>
        <groupId>org.glassfish.jersey.core</groupId>
        <artifactId>jersey-client</artifactId>
        <version>2.9.1</version>
    </dependency>

    <dependency>
<groupId>javax.ws.rs</groupId>
<artifactId>jsr311-api</artifactId>
<version>0.11</version>
 </dependency>

    <dependency>
        <groupId>joda-time</groupId>
        <artifactId>joda-time</artifactId>
        <version>2.3</version>
    </dependency>

    <!-- for deserialization -->
    <dependency>
        <groupId>com.google.code.gson</groupId>
        <artifactId>gson</artifactId>
        <version>2.2.4</version>
    </dependency>



</dependencies>

How are you running the code? Looks like you aren't including your dependencies when you run it. — bmargulies
I'm still new at this so I'm not quite sure, but we are supposed to clean and repackage every time we edit on any of the files in the project? — Kito
You start your program with an invalid class path. You should either bundle all dependencies with your distribution, or provide a path to dependencies in "-classpath" JavaVM argument. — Basilevs

bmargulies bmargulies · Accepted Answer · 2014-12-09T22:53:05

I'm fairly sure that I know your problem here.

You are using Maven to compile your code and make a jar files.

Then you are trying to execute that jar file from outside maven with some java command line or another.

When Maven calls Java to compile your code, it's adding all your dependencies to the classpath.

When you are running your code, you aren't.

You can configure the maven-dependency-plugin to write out a text file with the pathnames of all your dependencies, and then you can use that to build a command line. or you can use the maven-surefire-plugin to run tests, or the exec-maven-plugin to just launch a class, or the appassembler plugin to build a package with the dependencies and a command-line wrapper, or ...

Here's how to make the dependency plugin write out your class path.

<plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-dependency-plugin</artifactId>
    <executions>
      <execution>
        <id>build-classpath</id>
        <phase>generate-sources</phase>
        <goals>
           <goal>build-classpath</goal>
        </goals>
        <configuration>
         <outputFile>${project.build.directory}/classpath.txt</outputFile>
        </configuration>
      </execution>
    </executions>
  </plugin>

java.lang.noclassdeffounderror for Maven

2 Answers