Java Classnotfoundexception With Maven Dependency

Java ClassNotFoundException with maven dependency

Change provided to compile

Provided

This is much like compile, but indicates you expect the JDK or a container to provide the dependency at runtime. For example, when building a web application for the Java Enterprise Edition, you would set the dependency on the Servlet API and related Java EE APIs to scope provided because the web container provides those classes. This scope is only available on the compilation and test classpath, and is not transitive.

Maven dependency provided on submodule ear throws ClassNotFoundException

Because of transitive dependencies are not included when dependency is provided, so I had to restructure the modules this way.

Modules:

• app (pom)
• app-ear
  
  • jasperreports (compiled) MOVED FROM APP-COMMONS
• app-back
  
  • app-commons (provided)
• app-front
  
  • app-commons (provided)
• app-commons
  ...

I was not able to change app-commons dependency to compiled because it is dependent of app-front and app-back. In app-commons as compiled I have an @ApplicationScope class that it would produce ambiguous Beans pointing to the class in app-commons because of jakartaee context management.

ClassNotFoundException with Maven dependency system scoped

If you read the Maven documentation about this scope, it seems the expected behavior if your application server doesn't provide this library at runtime:

This scope is similar to provided except that you have to provide the
JAR which contains it explicitly.

The provided scope states :

This is much like compile, but indicates you expect the JDK or a
container to provide the dependency at runtime.

Not advised solution : add this library in the lib folder of your application server.

Cleaner solution : add this maven dependency in your maven repositories manually or with mvn install:install-file.

And remove the system scope of this dependency. It will use the default scope.

NoClassDefFoundError on Maven dependency

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.

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