Develop Reference

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 assign Websphere Shared libraries to project?

I have successfully created a Shared Library and deployed the EAR in WAS 7.
Before starting the application I have tried to assign the already created Shared Library to the project. But I'm getting the following error:
com.ibm.ws.webcontainer.webapp.WebApp log SRVE0292I: Servlet Message -
[isclite#isclite.war]:.action: ApplicationDeploymentDetailForm was
null.Creating new form bean and storing in session.
Could you please give some suggestion to fix this issue?

Migrating Application from WAS 6.1 to WAS 8.5

I am migrating applications from WAS 6.1 to WAS 8.5. Existing application works fine in WAS 6.1 but in WAS 8.5 while connecting to a bpm wsdl url, I am getting the following exception. The jar is present in WEB-INF/lib
java.lang.NoClassDefFoundError: org.apache.woden.resolver.URIResolver
at java.lang.J9VMInternals.verifyImpl(Native Method)
at java.lang.J9VMInternals.verify(J9VMInternals.java:85)
at java.lang.J9VMInternals.initialize(J9VMInternals.java:162)
at org.apache.axis2.deployment.ModuleDeployer.deploy(ModuleDeployer.java:65)
at org.apache.axis2.deployment.repository.util.DeploymentFileData.deploy(DeploymentFileData.java:136)
at org.apache.axis2.deployment.DeploymentEngine.doDeploy(DeploymentEngine.java:815)
at org.apache.axis2.deployment.RepositoryListener.loadClassPathModules(RepositoryListener.java:222)
at org.apache.axis2.deployment.RepositoryListener.init2(RepositoryListener.java:71)
at org.apache.axis2.deployment.RepositoryListener.<init>(RepositoryListener.java:64)
at org.apache.axis2.deployment.DeploymentEngine.loadFromClassPath(DeploymentEngine.java:177)
at org.apache.axis2.deployment.FileSystemConfigurator.getAxisConfiguration(FileSystemConfigurator.java:135)
at org.apache.axis2.context.ConfigurationContextFactory.createConfigurationContext(ConfigurationContextFactory.java:64)
at org.apache.axis2.context.ConfigurationContextFactory.createConfigurationContextFromFileSystem(ConfigurationContextFactory.java:210)
at org.apache.axis2.client.ServiceClient.configureServiceClient(ServiceClient.java:151)
at org.apache.axis2.client.ServiceClient.<init>(ServiceClient.java:144)

Switch the class loader to local first, parent last.
In application configuration go to:
Class loading and update detection
Change class loader order to local first
Save changes
Restart application server

For using third party Web service engine you need to set class loader to parent last and disable annotation scanning:
Set the DisableIBMJAXWSEngine property in the META-INF/MANIFEST.MF of
a WAR file or EJB module to true
See documentation for more details:
Using a third-party JAX-WS web services engine

How do I correct a Java LinkageError exception?

I am developing an application for WebSphere 6.1 which uses a Java servlet. Within my servlet, I have defined a serial vesion ID of 1L. Upon deploying and running my application, I am receiving a LinkageError of the following type (from the server log):
[5/9/11 15:14:26:868 EDT] 0000001c WebApp
E [Servlet Error]-[ManageRecordsConsumerServlet]: java.lang.Exception:
java.lang.LinkageError: LinkageError while defining class:
<redacted>.docindexupdate.batch.servlet.ManageRecordsConsumerServlet
Could not be defined due to: (<redacted>/docindexupdate/batch/servlet
/ManageRecordsConsumerServlet) class name must be a string at offset=2074
This is often caused by having a class defined at multiple
locations within the classloader hierarchy. Other potential causes
include compiling against an older or newer version of the class
that has an incompatible method signature.
I'm not sure what the issue is. I was seeing this previously before defining a serial version uid and figured that by defining that and being consistent, future updates to the class file would run successfully. There are no errors during compilation or deployment to the server. Is it possible that an older version of the servlet is cached somewhere on the WebSphere instance (I am only deploying on my dev machine at the moment)?
The
class name must be a string at offset=2074
line is also confusing.

I am suspecting you have a jar that is being loaded in two different classloaders. By that I mean, your websphere server on startup loads that jar or has an endorsed directory with that jar. Also your EAR you are deploying has that jar in its lib. The two can conflict at runtime
What I would suggest is to find out which jar ManageRecordsConsumerServlet belongs to and either remove it from your EAR lib or your Websphere endorsed lib (best would be your EAR lib).

It may be versioning, but I don't thing so.
When two classes loaded by different classloader, a ClassNotFoundException is normally thrown.
When a class is passed over a wire/loaded from disk cache, VersionMismatchException is normally thrown.
When a class with different method signatures is used, NoSuchMethodError or alike is thrown.
I think this case is a corrupted class file. Could be corrupted in cache or in the JAR.

Classloader problem with EJB

I'm working on a project which includes persistence library (JPA 1.2), EJB 3 and Web presentation layer (JSF). I develop application using Eclipse and application is published on Websphere Application Server Community Edition (Geronimo 2.1.4) through eclipse plugin (but the same thing happens if I publish manually). When publishing to server I get the following error:
java.lang.NoClassDefFoundError: Could not fully load class: manager.administration.vehicles.VehicleTypeAdminBean
due to:manager/vehicles/VehicleType
in classLoader:
org.apache.geronimo.kernel.classloader.TemporaryClassLoader#18878c7
at org.apache.xbean.finder.ClassFinder.(ClassFinder.java:177)
at org.apache.xbean.finder.ClassFinder.(ClassFinder.java:146)...
In web.xml I have reference to EJB:
<ejb-local-ref>
<ejb-ref-name>ejb/VehicleTypeAdmin</ejb-ref-name>
<ejb-ref-type>Session</ejb-ref-type>
<local>manager.administration.vehicles.VehicleTypeAdmin</local>
<ejb-link>VehicleTypeAdminBean</ejb-link>
</ejb-local-ref>
EJB project has a reference to persistence project, and Web project has references to both projects. I don't get any compilation errors, so I suppose classes and references are correct.
I don't know if it is app server problem, but I ran previously application on the same server using same configuration parameters.
Does anybody have a clue what might be the problem?

Looks almost like it couldn't find the class manager.vehicles.VehicleType when it was attempting to create/load the class manager.administration.vehicles.VehicleTypeAdminBean.
I've encountered similar problems before. When the class loader attempts to load the class it looks at the import statements (and other class usage declarations) and then attempts to load those classes and so on until it reaches the bottom of the chain (ie java.lang.Object). If it cannot find one class along the chain (in your case it looks like it cannot load VehicleType) then it will state that it cannot load the class at the top of the chain (in your case VehicleTypeAdminBean).
Is the VehicleType class in a different jar? If you have a web module and and EJB module do you have the jar containing the VehicleType class in the appropriate place(s). Sometimes with web projects you have to put the jars in the WebContent/WEB-INF/lib folder or it won't find them.
Are both of these projects deployed separately (ie. two ears? or one ear and one war?) or are they together (ie, one ear with jars and a war inside?). I'm assuming the second given you declared your EJB local?
The jars that you are dependent on also have to be declared in your MANIFEST.MF files in the projects that use it.
I'm kind of running on guesses since I do not know your project structure. Showing that would help quite a bit. But I'd still check on where VehicleType is located with regards to your EJB class. You might find it isn't where you think it is come packaging or runtime.

Thanks #Chris for WebContent/WEB-INF/lib idea ! it works for me by following these steps :
1- Export my EJBs to a JAR (MyEJBs.jar)
2- I created another jar with your_installation_path/IBM/SDP/runtimes/your_version/binCreateEJBStrub.bat via CMD.exe, by executing this command :
createEJBStubs.bat <my_path>/MyEJBs.jar -newfile –quiet
3- A new jar will be automatically created in the same directory as MyEJBs.jar named MyEJBs_withStubs.jar
4- Put your new jar in WebContent/WEB-INF/lib
5- Call your EJBs by :
MyEJBRemote eJBRemote;
InitialContext ic = new InitialContext();
obj = ic.lookup("your_ejb_name_jndi");
eJBRemote = (MyEJBRemote ) PortableRemoteObject.narrow(obj,
MyEJBRemote.class);
eJBRemote = (MyEJBRemote ) obj;
Now you can call your EJBs from another EAR