I'm having problems resolving sub-dependencies from a third-party package. I'm a bit of a Maven beginner. Basically it goes like this:
git clone git://github.com/unidata/thredds.git
cd thredds
mvn install
Everything works great and stuff is installed into ~/.m2. Now, I wrote my own code that uses the package that I just installed:
<?xml version="1.0" encoding="UTF-8"?>
<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>test</groupId>
<artifactId>test</artifactId>
<packaging>jar</packaging>
<version>0.1</version>
<name>Test Package</name>
<dependencies>
<dependency>
<groupId>edu.ucar</groupId>
<artifactId>netcdf</artifactId>
<version>4.3.8-SNAPSHOT</version>
</dependency>
</dependencies>
</project>
Ok, this also works great when I run mvn package. The netcdf artifact is found. Now, when I try to run my code, I start down a long ClassNotFoundException path, having to keep adding all of netcdf's dependencies to my classpath.
Am I doing something wrong, or should the thredds package and all its dependencies automatically be picked up?
edit: the thredds package has many sub-modules one of which is netcdf. My code only depends on the netcdf jar.
edit: the snapshot version is installed
$ ls -l ~/.m2/repository/edu/ucar/netcdf/4.3.8-SNAPSHOT/
total 4272
-rw-rw-r-- 1 nwatkins nwatkins 700 2012-03-29 23:23 maven-metadata-local.xml
-rw-rw-r-- 1 nwatkins nwatkins 182 2012-03-29 23:23 _maven.repositories
-rw-rw-r-- 1 nwatkins nwatkins 4357494 2012-03-29 23:23 netcdf-4.3.8-SNAPSHOT.jar
-rw-rw-r-- 1 nwatkins nwatkins 7840 2012-03-29 22:28 netcdf-4.3.8-SNAPSHOT.pom
edit: to run the code which is in a single file Test.java
$ java -cp target/test-0.1.jar Test
edit: first error message
$ java -cp target/test-0.1.jar Test
Exception in thread "main" java.lang.NoClassDefFoundError: ucar/ma2/InvalidRangeException
Caused by: java.lang.ClassNotFoundException: ucar.ma2.InvalidRangeException
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)
edit: then I just try to manually add the dependency jar to the class path
$ java -cp ../thredds/cdm/target/netcdf-4.3.8-SNAPSHOT.jar:target/test-0.1.jar Test
xception in thread "main" java.lang.NoClassDefFoundError: org/slf4j/LoggerFactory
at ucar.nc2.NetcdfFile.<clinit>(NetcdfFile.java:97)
at Test.main(Test.java:37)
Caused by: java.lang.ClassNotFoundException: org.slf4j.LoggerFactory
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)
... 2 more
The slf4j package is also in ~/.m2. I stopped trying to add things to the classpath after this as it seemed like the wrong approach.
at java.lang.ClassLoader.loadClass(ClassLoader.java:266)
Two solutions here (the cause of the problem has been explained in several answers):
1.Use maven exec plugin to launch your app:
<plugin>
<groupId>org.codehaus.mojo</groupId>
<artifactId>exec-maven-plugin</artifactId>
<executions>
<execution>
<goals>
<goal>exec</goal>
</goals>
</execution>
</executions>
<configuration>
<classpathScope>runtime</classpathScope>
<executable>java</executable>
<commandlineArgs>-classpath %classpath Test</commandlineArgs>
</configuration>
</plugin>
2.You can also package your jar with all its dependencies, using maven assembly plugin. To do that, you need to add the following to your plugins of your build:
<plugin>
<artifactId>maven-assembly-plugin</artifactId>
<version>2.3</version>
<configuration>
<descriptorRefs>
<descriptorRef>jar-with-dependencies</descriptorRef>
</descriptorRefs>
</configuration>
<executions>
<execution>
<id>build-package</id>
<phase>package</phase>
<goals>
<goal>single</goal>
</goals>
</execution>
</executions>
</plugin>
Then you can use the output jar created by maven assembly in your classpath arg
It sounds like you are trying to run your project from the target folder, and it is not seeing the transitive dependencies. You will need to use the maven dependencies plugin to have those dependencies copied over along with your jar file.
See also:
http://maven.apache.org/plugins/maven-dependency-plugin/copy-dependencies-mojo.html
You can then define the dependencies on these jars either manually, or via a generated manifest file:
http://maven.apache.org/shared/maven-archiver/index.html
The maven project that you've created only packages your classes into test-0.1.jar.
If you use a simple java command to run your application, you MUST provide all other jars that your project depends on to the -classpath ( or -cp ) switch ( or through CLASSPATH environment variable ).
There are alternative packaging configurations that can copy all required dependencies into a single jar, if that is what you want.
Here is the example, which is a verbatim copy from here -> http://www.sonatype.com/books/mvnref-book/reference/assemblies-sect-basics.html. I recommend that you read that whole chapter ( heck the whole book ) for better understanding.
<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/maven-v4_0_0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>org.sonatype.mavenbook.assemblies</groupId>
<artifactId>executable-jar</artifactId>
<version>1.0-SNAPSHOT</version>
<packaging>jar</packaging>
<name>Assemblies Executable Jar Example</name>
<url>http://sonatype.com/book</url>
<dependencies>
<dependency>
<groupId>commons-lang</groupId>
<artifactId>commons-lang</artifactId>
<version>2.4</version>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<artifactId>maven-assembly-plugin</artifactId>
<version>2.2-beta-2</version>
<executions>
<execution>
<id>create-executable-jar</id>
<phase>package</phase>
<goals>
<goal>single</goal>
</goals>
<configuration>
<descriptorRefs>
<descriptorRef>
jar-with-dependencies
</descriptorRef>
</descriptorRefs>
<archive>
<manifest>
<mainClass>org.sonatype.mavenbook.App</mainClass>
</manifest>
</archive>
</configuration>
</execution>
</executions>
</plugin>
</plugins>
</build>
</project>
If you want to have all the dependencies in classpath, when running your jar, you can use the maven-exec-plugin to run the program from withing maven, and have all the dependencies automatically added to your classpath.
You are missing the dependency for:
org/slf4j/LoggerFactory
which means in other words you need to add a dependency to your project:
<dependency>
<groupId>org.slf4j</groupId>
<artifactId>slf4j-log4j12</artifactId>
<version>1.6.4</version>
</dependency>
Assuming you are using log4j ?
And furthermore based on the missing class: ucar.ma2.InvalidRangeException it looks you need an other supplemental dependency except (May be take a look into the documentation if exists).
<dependency>
<groupId>edu.ucar</groupId>
<artifactId>netcdf</artifactId>
<version>4.3.8-SNAPSHOT</version>
</dependency>
Related
I am trying to run my java program TopicPublisher.java via command line. There are several dependencies specified through Maven.
In the directory with the pom.xml file, I ran the following commands: mvn clean, mvn package, and java -cp target/SOM_Enrichment-1.0-SNAPSHOT.jar TopicPublisher.
I get the following error:
Error: A JNI error has occurred, please check your installation and try again
Exception in thread "main" java.lang.NoClassDefFoundError: om/solacesystems/jcsmp/JCSMPStreamingPublishEventHandler
Below is a screenshot of my directory tree:
Any ideas how to solve this?
[EDIT]
Pom File:
<?xml version="1.0" encoding="UTF-8"?>
http://maven.apache.org/xsd/maven-4.0.0.xsd">
4.0.0
<groupId>CAMM</groupId>
<artifactId>SOM_Enrichment</artifactId>
<version>1.0-SNAPSHOT</version>
<build>
<plugins>
<plugin>
<artifactId>maven-assembly-plugin</artifactId>
<version>3.1.0</version>
<configuration>
<descriptorRefs>
<descriptorRef>jar-with-dependencies</descriptorRef>
</descriptorRefs>
</configuration>
<executions>
<execution>
<id>make-assembly</id> <!-- this is used for inheritance merges -->
<phase>package</phase> <!-- bind to the packaging phase -->
<goals>
<goal>single</goal>
</goals>
</execution>
</executions>
</plugin>
</plugins>
</build>
<dependencies>
<dependency>
<groupId>com.solacesystems</groupId>
<artifactId>sol-jcsmp</artifactId>
<version>[10,)</version>
</dependency>
</dependencies>
Your program loads classes from the com.solacesystems dependency in your pom.xml, but your classpath only contains your build artifact jar. Build a fat jar, as #Kerry suggests, or use the exec-maven-plugin to run from the command line. From within your project directory (where you execute mvn package), execute:
mvn exec:java -Dexec.mainClass=TopicPublisher
The plugin builds the classpath argument from the dependencies defined in your pom. See https://www.mojohaus.org/exec-maven-plugin/ for more options.
Without seeing your full POM.xml I am assuming you have not build the final artifact to be a 'fat jar'. By this I mean that the JAR not only contains your own classes but all the third party dependencies.
You would need to use something like the Maven assembly plugin or the Maven shade pluginto do this for you. From the screenshot though I see you are using IntelliJ so you should also be able to run through your IDE obviously for just testing purposes.
I'm using maven to manage my project.
This is my main file:
package com.sample;
import org.jsoup.Jsoup;
import org.jsoup.nodes.Document;
/**
* Hello world!
*
*/
public class App {
public static void main(String[] args )
{
try
{
/* String html = "<html><head><title>First parse</title></head>"
+ "<body><p>Parsed HTML into a doc.</p></body></html>";
Document doc = Jsoup.parse(html);*/
Document doc = Jsoup.connect("http://www.javatpoint.com").get();
String title = doc.title();
System.out.println("title is: " + title);
}
catch (Exception e)
{
System.out.println(e);
}
}
}
This is my pom.xml:
<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/maven-v4_0_0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.sample</groupId>
<artifactId>sample-pc</artifactId>
<packaging>jar</packaging>
<version>1.0-SNAPSHOT</version>
<name>sample-pc</name>
<url>http://maven.apache.org</url>
<dependencies>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>3.8.1</version>
<scope>test</scope>
</dependency>
<dependency>
<groupId>org.jsoup</groupId>
<artifactId>jsoup</artifactId>
<version>1.8.3</version>
<scope>compile</scope>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-jar-plugin</artifactId>
<configuration>
<archive>
<manifest>
<mainClass>com.sample.App</mainClass>
</manifest>
</archive>
</configuration>
</plugin>
</plugins>
</build>
</project>
When I run the following commands:
mvn clean package
java -jar target/sample-pc-1.0-SNAPSHOT.jar
I get the following errors:
Error: A JNI error has occurred, please check your installation and
try again Exception in thread "main" java.lang.NoClassDefFoundError:
org/jsoup/nodes/Document at
java.lang.Class.getDeclaredMethods0(Native Method) at
java.lang.Class.privateGetDeclaredMethods(Class.java:2701) at
java.lang.Class.privateGetMethodRecursive(Class.java:3048) at
java.lang.Class.getMethod0(Class.java:3018) at
java.lang.Class.getMethod(Class.java:1784) at
sun.launcher.LauncherHelper.validateMainClass(LauncherHelper.java:544)
at
sun.launcher.LauncherHelper.checkAndLoadMain(LauncherHelper.java:526)
Caused by: java.lang.ClassNotFoundException: org.jsoup.nodes.Document
at java.net.URLClassLoader.findClass(URLClassLoader.java:381) at
java.lang.ClassLoader.loadClass(ClassLoader.java:424) at
sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:331) at
java.lang.
However, if I directly run the app from eclipse, it runs without any errors. I am not sure why I cant run it from the command line.
Thanks
Your JAR does not include your dependencies after it has been packaged.
Add this code to your pom.xml under the plugins section:
<plugin>
<artifactId>maven-assembly-plugin</artifactId>
<executions>
<execution>
<phase>package</phase>
<goals>
<goal>single</goal>
</goals>
</execution>
</executions>
<configuration>
<descriptor>assembly.xml</descriptor>
</configuration>
</plugin>
And add the file assembly.xml to your resources directory:
<assembly xmlns="http://maven.apache.org/plugins/maven-assembly-plugin/assembly/1.1.3"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/plugins/maven-assembly-plugin/assembly/1.1.3 http://maven.apache.org/xsd/assembly-1.1.3.xsd">
<!-- TODO: a jarjar format would be better -->
<id>jar-with-dependencies</id>
<formats>
<format>jar</format>
</formats>
<includeBaseDirectory>false</includeBaseDirectory>
<dependencySets>
<dependencySet>
<outputDirectory>/</outputDirectory>
<useProjectArtifact>true</useProjectArtifact>
<unpack>true</unpack>
<scope>runtime</scope>
</dependencySet>
</dependencySets>
</assembly>
And then you can run mvn clean clean install or mvn package
Specifying a dependency to Maven makes it available for compiling -- not for running your code afterwards. Eclipse reads your POM and also sees the dependency.
Read up on the appassembler-maven-plugin or about making a MANIFEST.MF with a Class-Path to solve your problem.
As an aside, I'm using IntelliJ IDEA with Maven support, and my setup is very similar to yours except for the scope: compile element in the dependency declaration. Looks like the IDE takes care of these specific requirements.
Unless you are specifically looking to understand Maven, you could consider using such an IDE to handle the minutiae for you.
Maven jar plugin is created on the package phase, and the jar created by this plugin is, by default, not executable, though you have specified the class that contains main method in the generated MANIFEST.MF file:
<archive>
<manifest>
<mainClass>com.sample.App</mainClass>
</manifest>
</archive>
so you was able to execute it, but this JAR that you have assembled only contains the compiled source code file (.class files generated from your source .java files) and the resources (typically located in src/main/resource folder, though this location can be overrided, extended e.t.c.), that's all.
So, this jar is not a fat JAR (you can create one with maven shade plugin, see official usage example here).
Also there is no Class-Path entry specified in the MANIFEST.MF within the JAR (you can specify the Class-Path entry in the maven jar plugin configuration, see here official example, also take a look into maven-dependency-plugin, also widely used in this cases) - so, JVM is throwing NoClassDefFoundError, because at runtime it is not able to find some classes, and this happens because JVM has no idea where to search for them
Ponder on it - classes of your dependencies are not present in the JAR itself, because it is not a fat Jar you are assembling, neither there is a classpath specified in your manifest.
So, I think the easiest solution would be to include the maven-shade-plugin into your build and assemble an uber jar. Include the following plugin into your build:
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-shade-plugin</artifactId>
<version>3.3.0</version>
<executions>
<execution>
<phase>package</phase>
<goals>
<goal>shade</goal>
</goals>
</execution>
</executions>
</plugin>
Hope it helped, have a nice day.
So I run maven package to build my dependencies into a jar. However, I need Maven to ignore any compilation errors and package the jar regardless.
How would this be accomplished? My pom.xml is as follows:
<?xml version="1.0" encoding="UTF-8"?>
<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">
<!-- Project specific stuff would be here... -->
<build>
<sourceDirectory>wherever</sourceDirectory>
<plugins>
<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>
<dependencies>
<dependency>
<groupId>com.googlecode.json-simple</groupId>
<artifactId>json-simple</artifactId>
<version>1.1.1</version>
</dependency>
<dependency>
<groupId>commons-io</groupId>
<artifactId>commons-io</artifactId>
<version>2.4</version>
</dependency>
<!-- etc... -->
</dependencies>
<properties>
<maven.compiler.source>1.8</maven.compiler.source>
<maven.compiler.target>1.8</maven.compiler.target>
</properties>
</project>
Searching through SO only showed me how to ignore compilation errors from unit testing. I simply want my package to be compiled despite any errors in the code.
Edit: People seem to be bashing on me. I've been doing Java for 5 years. I know you're not supposed to compile with errors. I know what it entails.
My boss programs with me. He specifically said, "I can compile with errors in Eclipse, so compile with errors in Maven." It's not because I am ignorant, or because I refuse to accept my mistakes. It is because that is what I was specifically ordered to do. I did not ask this question because I am incompetent as many of you would like to assume.
Hate on me all you want, just know that you are doing so unfairly.
Use the exclude option to the compiler plugin to exclude the classes that have compile errors.
Building on Top of #wings Answer
You can use the flag failOnError=false in your pom, too
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<configuration>
<failOnError>false</failOnError>
</configuration>
</plugin>
or via command line
mvn package -Dmaven.compiler.failOnError=false
Maybe this is what you want:
https://maven.apache.org/plugins/maven-compiler-plugin/compile-mojo.html#failOnError
Set failOnError=false to ignore compilation errors.
When you run maven package. That means maven will run all phases before "package" phase. Hence maven compile will be triggered for sure. And because of compilation error, maven will stop at "compile" phase.
To package your project even with compilation error. I think you should use "maven assembly plugin" to package your depensencies ONLY and the phase of that plugin should be something before "compile". ex: "process-sources" or "process-resources".
By that way, before maven compiles your project's source code, you will have a bundle which includes all dependencies. Of course, maven will stop at the "compile" phase again. But you already have what you want.
Hope this help.
If it's just about the dependencies there's dependency:copy-dependencies:
Goal that copies the project dependencies from the repository to a defined location.
Use assembly:single with a user-defined descriptor to create the JAR with the dependencies from the location defined above:
Assemble an application bundle or distribution from an assembly descriptor.
I have a multi module project. The aspect is currently added to the "core" project. When doing a mvn clean install here it works. However trying to do a mvn clean install on parent project it fails with this error when compiling one of the other projects:
The type org.hibernate.annotations.CacheConcurrencyStrategy cannot be resolved. It is indirectly referenced from required .class files
If I add the Hibernate core dependency in that project too it works, but adding dependencies to projects that shouldn't have the dependency does not make sense - so it is not a solution. When compiling with javac it works fine.
What is the reason? And how can I fix it so I can use the AspectJ compiler without leaking dependencies to projects that shouldn't have that?
I have this configuration in the parent POM:
<build>
<plugins>
<plugin>
<groupId>org.codehaus.mojo</groupId>
<artifactId>aspectj-maven-plugin</artifactId>
<version>1.5</version>
<configuration>
<source>1.6</source>
<target>1.6</target>
<complianceLevel>1.6</complianceLevel>
</configuration>
<executions>
<execution>
<goals>
<goal>compile</goal>
</goals>
</execution>
</executions>
</plugin>
</plugins>
</build>
Update
I just found out. Running mvn clean install fails every time. However, running mvn [clean] install one time fails. Then running mvn install without clean works. I see that the builddef.lst in the target folder is the reason why it works and fails based on whether or not you run clean. So now my question is: How do you automatically generate this file?
Parent POM-file:
<?xml version="1.0" encoding="UTF-8"?>
<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/maven-v4_0_0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.mycompany</groupId>
<artifactId>core-lib</artifactId>
<name>core-lib</name>
<packaging>pom</packaging>
<build>
<plugins>
<plugin>
<groupId>org.codehaus.mojo</groupId>
<artifactId>aspectj-maven-plugin</artifactId>
<version>1.5</version>
<configuration>
<source>1.6</source>
<target>1.6</target>
<complianceLevel>1.6</complianceLevel>
</configuration>
<executions>
<execution>
<goals>
<goal>compile</goal>
</goals>
</execution>
</executions>
</plugin>
</plugins>
</build>
<dependencies>
<dependency>
<groupId>org.aspectj</groupId>
<artifactId>aspectjrt</artifactId>
<version>1.7.4</version>
</dependency>
</dependencies>
<modules>
<module>core-xyz</module>
<module>core-xyz2</module>
</modules>
</project>
Enable debug on the maven invocation to dig deeper. You should observe that the aspectj compile is only being invoked during the first maven invocation with the clean. Since the builddef.lst already exists after the first invocation, invoking without clean skips the aspectj compile.
This aspectj compile plugin behavior has been observed previously and was described here:
http://out-println.blogspot.com/2007/08/compile-time-checks-with-aspectj-part-2.html?m=1
You will need to look deeper to address the underlying issue, but as one commenter has already suggested, the aspectj compiler should only be enabled in modules that require it.
Otherwise, the additional dependencies are required for the aspectj compile, as you have already observed. I have incorporated aspectj compile into my own work without issue by restricting it to only the modules that require it.
According to the AspectJ compiler Maven plugin you could set up the argumentFileName to locate an existing builddef.lst.
So you can generate the builddef.lst and copy it to your resources folder, and instruct the AspectJ Maven plugin to use that file.
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