I have a SpringbootApplication that provides a REST API, let's call it fetchPrediction.
This fetchPrediction API uses some classes defined inside a JAR file, which is a JNI.
My application compiles and starts, however, if I call the fetchPrediction API it fails.
When I do jar -xvf on the created jar after mvn clean install, I do not see the classes that should be picked up by including the jar dependency.
Also, when I try to run the Jar file I see ClassNotDefinedException for the classes inside the JAR.
How can I do this properly?
Currently I am importing the JAR dependency as follows:
<dependency>
<groupId>jarcom.jarlib</groupId>
<artifactId>jarname</artifactId>
<version>1.0</version>
<scope>system</scope>
<systemPath>${project.basedir}/jarname.jar</systemPath>
</dependency>
In an spring boot application you usually do not have JNI parts. Furthermore the spring-boot-maven-plugin by default does not include dependencies with <scope>system</scope> that's the reason why you do not see the jar file in the resulting jar.
You have to have to configure the spring-boot-maven-plugin and set the includeSystemScope to true as described in the docs for the plugin.
<project>
...
<build>
...
<plugins>
...
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
<version>2.2.4.RELEASE</version>
<executions>
<execution>
<id>repackage</id>
<goals>
<goal>repackage</goal>
</goals>
<configuration>
<includeSystemScope>true</includeSystemScope>
</configuration>
</execution>
</executions>
...
</plugin>
...
</plugins>
...
</build>
...
</project>
This question already has answers here:
Add external library .jar to Spring boot .jar internal /lib
(8 answers)
Closed 4 years ago.
When I mvn clean package the project and run it with java -jar target/project.jar it throws an error that it cannot find some class from an external jar.
Steps taken
All external jars are in a folder of my project: /jars or /jars/morejars/
Adding the jars to the build path: In Eclipse I right click on project, go to build path and select add external archives. I can see that eclipse creates a library folder "referenced libraries" below the "Maven dependencies" folder. When I check project -> Properties -> Java Build Path -> Libraries I can see all the imported jars.
Some of those external jars are described as <dependency> (with <systemPath) in pom.xml, so they will not be seen in Referenced Libraries but in Maven dependencies (interestingly, the class that cannot be found when running my packaged project is in an external jar that doesn't reside in Referenced Libraries but Maven dependencies)
e.g.
<dependency>
<groupId>external.jar.groupid</groupId>
<artifactId>external.jar.artifactid</artifactId>
<version>1.0</version>
<scope>system</scope>
<systemPath>${basedir}/jars/external-jar.jar</systemPath>
</dependency>
Use the maven assembly plugin (as described here), this is my full <build> config:
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
<plugin>
<artifactId>maven-assembly-plugin</artifactId>
<executions>
<execution>
<phase>package</phase>
<goals>
<goal>single</goal>
</goals>
</execution>
</executions>
<configuration>
<descriptorRefs>
<descriptorRef>jar-with-dependencies</descriptorRef>
</descriptorRefs>
</configuration>
</plugin>
</plugins>
</build>
Run mvn clean package -> BUILD SUCCESS
java -jar target/project.jar -> Cannot find some.class from external.jar
Thanks for the help
The problem is clearly with dependencies. While your application starts loading it looking for required classes to run properly. While it loading a class from a jar library and that library class also refer to some other class from a another jar library file but that library (jar file) is not available in your class path, it will give you the above error. So check for maven dependency and get all the jars required by your application. Also based on error message also you can add the jar reference in your pom.xml file. For example if you get an error like Failed to load com.apache.some.Example.class just google the Example.class jar file and get it from maven repository.
Hope this will help you.
I have a maven project that I just added some features to and in order to do so I had to add a local jar dependency. I have added this jar file to the lib folder of the project on Github, and I want to make it so anyone who downloads the project off Github can install that jar to their m2 directory without having to use the maven install:install-file command through command line. The POM file has the dependency already but I need a way to programmatically install the jar file when building the snapshot with mvn install.
Thoughts?
Option 0:
Deploy the jar file to a public or comany-wide maven repository. If the project producing this jar is also a git(hub) project, consider using a service like Jitpack
Option 1:
Ugly, but could work.
<dependency>
<groupId>com.bar</groupId>
<artifactId>foo</artifactId>
<version>42</version>
<scope>system</scope>
<systemPath>${project.basedir}/lib/foo-42.jar</systemPath>
</dependency>
Option 2:
Even more ugly, but could work even better.
<build>
<plugins>
<plugin>
<artifactId>maven-install-plugin</artifactId>
<executions>
<execution>
<id>install-foo</id>
<goals>
<goal>install-file</goal>
</goals>
<phase>generate-sources</phase>
<configuration>
<groupId>com.bar</groupId>
<artifactId>foo</artifactId>
<version>42</version>
<file>${project.basedir}/lib/foo-42.jar</file>
</configuration>
</execution>
</executions>
</plugin>
</plugins>
</build>
My first use of Maven and I'm stuck with dependencies.
I created a Maven project with Eclipse and added dependencies, and it was working without problems.
But when I try to run it via command line:
$ mvn package # successfully completes
$ java -cp target/bil138_4-0.0.1-SNAPSHOT.jar tr.edu.hacettepe.cs.b21127113.bil138_4.App # NoClassDefFoundError for dependencies
It downloads dependencies, successfully builds, but when I try to run it, I get NoClassDefFoundError:
Exception in thread "main" java.lang.NoClassDefFoundError: org/codehaus/jackson/JsonParseException
at tr.edu.hacettepe.cs.b21127113.bil138_4.db.DatabaseManager.<init>(DatabaseManager.java:16)
at tr.edu.hacettepe.cs.b21127113.bil138_4.db.DatabaseManager.<init>(DatabaseManager.java:22)
at tr.edu.hacettepe.cs.b21127113.bil138_4.App.main(App.java:10)
Caused by: java.lang.ClassNotFoundException: org.codehaus.jackson.JsonParseException
at java.net.URLClassLoader$1.run(URLClassLoader.java:217)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:205)
at java.lang.ClassLoader.loadClass(ClassLoader.java:321)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:294)
at java.lang.ClassLoader.loadClass(ClassLoader.java:266)
... 3 more
My pom.xml is like this:
<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>tr.edu.hacettepe.cs.b21127113</groupId>
<artifactId>bil138_4</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>jar</packaging>
<name>bil138_4</name>
<url>http://maven.apache.org</url>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
</properties>
<dependencies>
<dependency>
<groupId>org.codehaus.jackson</groupId>
<artifactId>jackson-core-asl</artifactId>
</dependency>
<dependency>
<groupId>org.codehaus.jackson</groupId>
<artifactId>jackson-mapper-asl</artifactId>
</dependency>
</dependencies>
<dependencyManagement>
<dependencies>
<dependency>
<groupId>org.codehaus.jackson</groupId>
<artifactId>jackson-core-asl</artifactId>
<version>1.9.6</version>
</dependency>
<dependency>
<groupId>org.codehaus.jackson</groupId>
<artifactId>jackson-mapper-asl</artifactId>
<version>1.9.6</version>
</dependency>
</dependencies>
</dependencyManagement>
</project>
Can anyone help me?
By default, Maven doesn't bundle dependencies in the JAR file it builds, and you're not providing them on the classpath when you're trying to execute your JAR file at the command-line. This is why the Java VM can't find the library class files when trying to execute your code.
You could manually specify the libraries on the classpath with the -cp parameter, but that quickly becomes tiresome.
A better solution is to "shade" the library code into your output JAR file. There is a Maven plugin called the maven-shade-plugin to do this. You need to register it in your POM, and it will automatically build an "uber-JAR" containing your classes and the classes for your library code too when you run mvn package.
To simply bundle all required libraries, add the following to your POM:
<project>
...
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-shade-plugin</artifactId>
<version>3.4.1</version>
<executions>
<execution>
<phase>package</phase>
<goals>
<goal>shade</goal>
</goals>
</execution>
</executions>
</plugin>
</plugins>
</build>
...
</project>
Once this is done, you can rerun the commands you used above:
$ mvn package
$ java -cp target/bil138_4-0.0.1-SNAPSHOT.jar tr.edu.hacettepe.cs.b21127113.bil138_4.App
If you want to do further configuration of the shade plugin in terms of what JARs should be included, specifying a Main-Class for an executable JAR file, and so on, see the "Examples" section on the maven-shade-plugin site.
when I try to run it, I get NoClassDefFoundError
Run it how? You're probably trying to run it with eclipse without having correctly imported your maven classpath. See the m2eclipse plugin for integrating maven with eclipse for that.
To verify that your maven config is correct, you could run your app with the exec plugin using:
mvn exec:java -D exec.mainClass=<your main class>
Update: First, regarding your error when running exec:java, your main class is tr.edu.hacettepe.cs.b21127113.bil138_4.App. When talking about class names, they're (almost) always dot-separated. The simple class name is just the last part: App in your case. The fully-qualified name is the full package plus the simple class name, and that's what you give to maven or java when you want to run something. What you were trying to use was a file system path to a source file. That's an entirely different beast. A class name generally translates directly to a class file that's found in the class path, as compared to a source file in the file system. In your specific case, the class file in question would probably be at target/classes/tr/edu/hacettepe/cs/b21127113/bil138_4/App.class because maven compiles to target/classes, and java traditionally creates a directory for each level of packaging.
Your original problem is simply that you haven't put the Jackson jars on your class path. When you run a java program from the command line, you have to set the class path to let it know where it can load classes from. You've added your own jar, but not the other required ones. Your comment makes me think you don't understand how to manually build a class path. In short, the class path can have two things: directories containing class files and jars containing class files. Directories containing jars won't work. For more details on building a class path, see "Setting the class path" and the java and javac tool documentation.
Your class path would need to be at least, and without the line feeds:
target/bil138_4-0.0.1-SNAPSHOT.jar:
/home/utdemir/.m2/repository/org/codehaus/jackson/jackson-core-asl/1.9.6/jackson-core-asl-1.9.6.jar:
/home/utdemir/.m2/repository/org/codehaus/jackson/jackson-mapper-asl/1.9.6/jackson-mapper-asl-1.9.6.jar
Note that the separator on Windows is a semicolon (;).
I apologize for not noticing it sooner. The problem was sitting there in your original post, but I missed it.
You have to make classpath in pom file for your dependency. Therefore you have to copy all the dependencies into one place.
Check my blog.
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-dependency-plugin</artifactId>
<version>2.1</version>
<executions>
<execution>
<id>copy-dependencies</id>
<phase>package</phase>
<goals>
<goal>copy-dependencies</goal>
</goals>
<configuration>
<outputDirectory>${project.build.directory}/lib</outputDirectory>
<overWriteReleases>false</overWriteReleases>
<overWriteSnapshots>false</overWriteSnapshots>
<overWriteIfNewer>true</overWriteIfNewer>
</configuration>
</execution>
</executions>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-jar-plugin</artifactId>
<version>2.4</version>
<configuration>
<archive>
<manifest>
<addClasspath>true</addClasspath>
<classpathPrefix>lib/</classpathPrefix>
<mainClass>$fullqualified path to your main Class</mainClass>
</manifest>
</archive>
</configuration>
</plugin>
</plugins>
</build>
This is due to Morphia jar not being part of your output war/jar. Eclipse or local build includes them as part of classpath, but remote builds or auto/scheduled build don't consider them part of classpath.
You can include dependent jars using plugin.
Add below snippet into your pom's plugins section
<plugin>
<artifactId>maven-assembly-plugin</artifactId>
<version>3.0.0</version>
<configuration>
<descriptorRefs>
<descriptorRef>jar-with-dependencies</descriptorRef>
</descriptorRefs>
</configuration>
</plugin>
For some reason, the lib is present while compiling, but missing while running.
My situation is, two versions of one lib conflict.
For example, A depends on B and C, while B depends on D:1.0, C depends on D:1.1, maven may
just import D:1.0. If A uses one class which is in D:1.1 but not in D:1.0, a NoClassDefFoundError will be throwed.
If you are in this situation too, you need to resolve the dependency conflict.
I was able to work around it by running mvn install:install-file with -Dpackaging=class. Then adding entry to POM as described here:
Choosing to Project -> Clean should resolve this
I build my project with mvn clean install, however I want to generate a subfolder in the target folder and put the generated jar file in there. I saw these two questions Maven: specify the outputDirectory only for packaging a jar? and maven: how to place the output jar into another folder however their answer doesn't seem to work.
This is how my maven build looks like:
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-jar-plugin</artifactId>
<version>2.3.1</version>
<configuration>
<outputDirectory>${project.build.directory}/blah</outputDirectory>
</configuration>
</plugin>
</plugins>
</build>
However I get the .jar file still in target directory. I also noticed that the project packaging is set as <packaging>eclipse-plugin</packaging> if I change this to jar, then it works fine, however I do need it to be eclipse-plugin. I am also using tycho for the eclipse plugin. Am I missing something that was not mentioned before?
From your packaging of eclipse-plugin I'm guessing you're using Tycho. Tycho doesn't seem to use any of the maven plugins, so configuring the maven-jar-plugin isn't going to help. Instead try configuring the tycho-packaging-plugin, specifically the buildDirectory property:
<plugin>
<groupId>org.eclipse.tycho</groupId>
<artifactId>tycho-packaging-plugin</artifactId>
<version>${tycho-version}</version>
<configuration>
<buildDirectory>${project.build.directory}/blah</buildDirectory>
</configuration>
</plugin>