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Referencing an external class from a Jersey REST web app

I am trying a simple example of creating a RESTful API. I used the Maven jersey-quickstart-webapp archtype to create a Jersey web app. In a separate project I created a simple class: SimpleClass, which only has one method that returns "hello". I am trying to create an instance of that class in my method in the web app (I am using the default MyResource class) and call its method to get "Hello". I exported the project with the SimpleClass to a JAR file, and added that file to the build path for my Jersey project, and imported the relevant package.
When I run the web app on a local server, and call the MyResource method, I get an error with the root cause (just the top few rows):
java.lang.NoClassDefFoundError: Lorg/test/simple/SimpleClass;
java.lang.Class.getDeclaredFields0(Native Method)
java.lang.Class.privateGetDeclaredFields(Class.java:2583)
java.lang.Class.getDeclaredFields(Class.java:1916)
So, it can't find the SimpleClass class.
What am I doing wrong here? I'd really appreciate any help!
Thanks,
Yariv.
New info: I tried to create a RESTful web service without Maven. I successfully created the project with a simple "Hello World" example, and then I tried to add my own class from another project: I imported the .jar, added it to the build path, and created a class in the web service that creates an instance of my class when a GET is made to the server. My class happens to include (as members) instances of other classes, one of which connects to a MongoDB database, and when I run the service, I again get a HTTP 500 error as follows:
A MultiException has 2 exceptions. They are:
1. java.lang.NoClassDefFoundError: com/mongodb/DBObject
2. java.lang.IllegalStateException: Unable to perform operation: create on org.notes.server.NotesServer
Adding the MongoDB jar to the web project did not help. I must be missing something big here. What should I do to call code I created in another project (with a set of dependencies there) in my web service?
I'll appreciate any help I can get, I am getting nowhere with this...

I was able to resolve all these issues by adding all the relevant JARs to the deployment assembly (right-click on the project, click Properties, then select Deployment Assembly and add all the JARs that my class depends on, as well as its own JAR).
Thanks for your help, radai!

How to specify order of JAR class loading in weblogic

I have an EAR file that contains two different jars that share some classes with an identical package.class name. These JARs are deployed in my APP-INF/lib directory.
Let's say A jar contains the latest version of classes and B contains the old version of classes. When a class is referenced Weblogic looks first into B jar and loads the old version which break some functionality.
How can I tell Weblogic to load jar A before B from APP-INF/lib? I need to define a specific order to avoid loading old classes.
I have already tried adding A jar to <classloader-structure> in weblogic-application.xml like so:
EAR structure:
EAR
\--->A.jar
\--->webapp.war
.....
weblogic-application.xml:
<classloader-structure>
<module-ref>
<module-uri>A.jar</module-uri>
</module-ref>
.......
</classloader-structure>
but then it throws error saying
weblogic.management.DeploymentException: classloader-structure element in weblogic-application.xml is referencing the module-uri A.jar which does not exist in this application.
Also one thing to remember is that A.jar is not a module, war or EJB it just a plain hibernate library: hibernate-jpa-2.0-api-1.0.1.Final.jar
I am using Weblogic 12c version.

You need to set parent last strategy for class-loader, refer http://www.rgagnon.com/javadetails/java-0551.html, as i remember there is a GUI in weblogic server to do the same.

Weblogic Preprosessor in Maven

I have some Java code that is currently packaged in the BEA Workshop for WebLogic Platform.
My task is to migrate the structure of the project (without actually touching the code) to a maven structure to be packaged from command line (or from eclipse m2e).
Problem is, the code has some annotations like this:
#WebService(serviceName = "Cancelacion", targetNamespace =
"http://www.banamex.com.mx/OtorgamientoPension/cancelacion")
#WLHttpTransport(contextPath = "OtorgamientoPension", serviceUri =
"cancelacion", portName = "cancelacionSOAP")
#Policies({
#Policy(uri="policy:Wssp1.2-Wss1.0-X509-Basic256.xml", direction = Policy.Direction.inbound),
})
public class CancelacionPortImpl implements CancelacionPort {
...
}
That create some configuration inside the war (a mysterious meta-inf inside the web-inf and plenty of xml).
Please notice the #Policies which is from a WebLogic library. It creates some security-related config and that's (alongside the ws stuff) is what i want to generate.
Is there a way to process this from maven?
EDIT
So far I have tried with the weblogic-maven-plugin. It didn't work (also, due to internal policies, the not-so-straightforward way of installing this plugin is not an option).
I'm trying to find a vague reference a co-worker gave me about certain "jtools" compiler... but can't find anything that comes with that name and have some relation with WebLogic.
So the #Policies annotation is still a problem.
Right now I'm looking for a eclipse-plugin that does this, based on the premise that was the IDE who process that annotations.
For the wsdl issue, I find out that the namespace definition whas wrong. I corrected it and now it's working. I used the jaxb2-maven-plugin because I have no knowledge of jaxws-maven-plugin and I already had the config of the former.

Looks like you might need some Weblogic classes on your classpath. Short of uploading these to your own private Maven repository, you might consider checking out the Oracle Maven repository to find the Weblogic artifacts you need. Since these are likely container-provided jars (i.e. you don't need to package them in your war), you'll want to define them with a scope of "provided" in your dependencies, e.g. <scope>provided</scope>.

NoClassDefFoundException in N-tier application

I am building a project for a class that I am taking, and it consists of 4 modules
-impl (business logic/dao access)
-ejb (encapsulates business logic and provides access to it via a remote interface)
-war (web tier)
-ear (contains the war and ejb modules)
One utility class that I have inside the impl is able to populate an H2 database. It does this by running an ingestor that reads in an processes an xml file that resides in a maven repository, using various dao classes/methods to ingest the data:
String fileName = "xml/proj-data.xml";
InputStream is = Thread.currentThread().getContextClassLoader().getResourceAsStream(fileName);
When I run the ingestor through a unit test, it runs fine, but when I have everything layered, I get the NoClassDefFoundException on xml/proj-data.xml
So the basic outline that I have is:
-the war has dependencies on the impl and ejb modules
-the ejb has dependency on the impl module
-the ear has dependency on the impl, ejb, and war
This is a maven project. When I deploy the EAR to the server, the start page for the war is displayed (as I expect).
-The html page has a button that when pressed, does a post to a servlet
-The servlet has an ejb injected into it that it calls (via its remote interface).
-The ejb method makes a call back to the populate method in the impl, and thats when the exception happens, and I get a webpage back showing the exception.
Do I need to declare that repository in the WAR pom file as well?

In typing the question, I think I know what the problem may be. The repository that the xml file resides in is declared in the root pom for the project(the impl parent), NOT the pom for the impl module. Since the impl is the module that gets packaged with the EAR, I may need to declare the repository in the impl pom file as well.

Annotation-specified bean name conflicts with existing, non-compatible bean definition

I'm using Spring 2.5.4 and am creating a Java application that I'm deploying onto Weblogic.
I have a class in an external library (which included in the WEB-INF/classes directory of the resulting WAR file of my application) that I want to use in my code. I've created an instance variable for an object of the class in my code and added the #Autowired annotation and a getter and setter. In my application context file I have declared a bean of the library class' type and added the following:
<context:annotation-config />
<context:component-scan base-package="com.mycompany" />
... in order to register an AutowiredAnnotationBeanPostProcessor that will scan the classes and process the annotation.
When I try and deploy the application, I get the following error:
java.lang.IllegalStateException: Annotation-specified bean name 'myBean' for bean
class [com.mycompany.package.ClassName] conflicts with existing, non-compatible
bean definition of same name and class [com.mycompany.otherPackage.ClassName]
I think this is because there's a class in the library which has the same name as one in my application code (both class' package names start with "com.mycompany"). Nb. this is NOT the class that I have added, but a different one. Is there any way I can circumvent this problem without changing the name of the class in my application?
Thanks for any assistance.

Old question but throwing my 2c of bad experience with similar problem.
If you have 2 classes with same name, but in different packages was there a time when you had your other class referenced by the failing Spring context? If so, I'd recommend to clean the AS cached files (typically the place where the WAR is extracted), clean/rebuild your WAR and deploy again. Restarting the app server is also recommended.
I found that application servers and web containers alike (Weblogic, WAS, Jboss, Tomcat) tend to leave behind the old classes and when application is deployed those stale .class files are loaded in JVM via some old references, which most of the time messes up the Spring context loader.
Typical scenario is when you have renamed/moved a class from one package to another, or even kept the package name the same but moved it to another module (jar). In such cases cached (left over) files in the AS work directory can cause big headaches. Wiping out the work directory in your AS should resolve the issue outright.

You should use #qualifier to avoid this kind of conflict please refer section 3.9.3.

I fixed the problem by removing the autowiring completely and accessing the bean by explicitly creating a reference to it through the application context and the getBean() method.

This would better fit as a comment to #Pavel Lechev's answer, but I don't have enough rep to comment yet.
For other's finding this, here's what I did to solve this problem. I am using Wildfly 9.0.2.Final and, IntelliJ IDEA 2016.1.3 Build #IU-145.1617. These steps should presumably work with JBoss as well.
Stop Wildfly server.
Navigate to $WILDFLY_HOME/standalone/. Delete the three following folders: lib/, log/ and temp/.
In IntelliJ, Build > Build Artifacts > All Artifacts > Clean (or just the artifacts you are deploying).
In IntelliJ, Build > Rebuild Project
Restart Wildfly and redeploy your artifact(s).
These steps remedied my issue of duplicate bean names detected in the Spring context after refactoring a package name upstream from a couple of Controllers.