Referencing an external class from a Jersey REST web app - java

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!

Related

Liferay: NoClassDefFoundError when calling a local service

I've got two Liferay portlets.
The first one manages persistence, I've created some entities and run service builder. After that, I've created a couple of methods in MyEntityLocalServiceImpl and run service builder again to get all the related methods.
I generate the jar and the war of this portlet, install the war in my Liferay instance and copy the jar at tomcat's /lib/ext
From my second portlet, I call MyEntityServiceUtil.myMethod(myParams) and, at execution time, it throws:
10:51:59,458 ERROR [http-bio-8080-exec-8][PortletServlet:116] javax.portlet.PortletException: java.lang.NoClassDefFoundError: com/liferay/portal/service/BaseService
javax.portlet.PortletException: java.lang.NoClassDefFoundError: com/liferay/portal/service/BaseService
at com.liferay.portal.kernel.portlet.LiferayPortlet.callActionMethod(LiferayPortlet.java:181)
at com.liferay.util.bridges.mvc.MVCPortlet.callActionMethod(MVCPortlet.java:249)
at com.liferay.portal.kernel.portlet.LiferayPortlet.processAction(LiferayPortlet.java:90)
at com.liferay.util.bridges.mvc.MVCPortlet.processAction(MVCPortlet.java:212)
at com.liferay.portlet.FilterChainImpl.doFilter(FilterChainImpl.java:71)
at com.liferay.portal.kernel.portlet.PortletFilterUtil.doFilter(PortletFilterUtil.java:48)
at com.liferay.portal.kernel.servlet.PortletServlet.service(PortletServlet.java:112)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:731)
...
I can see portal-service.jar at tomcat's /lib/ext, containing BaseService.class
Any idea why is it not being found at execution time? Thanks!

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.

Using Coda Hale Yammer Metrics library in Websphere Application Server 7

I am trying to add metrics library to existing webservice on WAS 7. I am getting below error
Error 404: javax.servlet.UnavailableException: SRVE0203E: Servlet [AdminServlet]: com.yammer.metrics.reporting.AdminServlet was found, but is missing another required class. SRVE0206E: This error typically implies that the servlet was originally compiled with classes which cannot be located by the server. SRVE0187E: Check your class path to ensure that all classes required by the servlet are present.SRVE0210I: This problem can be debugged by recompiling the servlet using only the classes in the application's runtime class path SRVE0234I
What are the other run-time dependencies required for metrics-servlet-2.2.0?
I have metrics-core-2.2.0.jar and metrics-servlet-2.2.0.jar in my WEB-INF\lib folder.
Threads, ping and healthcheck servlets work fine.
I think your missing some more required jars, are you not using maven or gradle for dependency management
Please refer here to know all required jars that metrics-servlet-2.2.0.jar depends on. http://mvnrepository.com/artifact/com.yammer.metrics/metrics-servlets/3.0.0-BETA1
My suggestion is, it is always difficult to maintain dependencies without Maven/Gradle or any other build tools :).

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

web client for web service

I've a web-service that works fine when I access them from a J2SE (desktop) application. To access this service I do follow:
generate stub classes by wsdl link using java wsimport tool
then I create service using generated classes and run one of wsdl operations.It looks like this:
MyWebServiceService webService = new MyWebServiceService();
MyWebService port = webService.getMyWebServicePort();
webService.run("XYZ");
As I sad it work fine when I use it in a standalone application.
But...when I try to access web-service in the same way but from servlet-client, using generated stubs I get following error:
java.lang.ClassCastException: com.sun.xml.bind.v2.runtime.JAXBContextImpl cannot be cast to com.sun.xml.bind.api.JAXBRIContext
org.jboss.ws.metadata.umdm.EndpointMetaData.eagerInitializeAccessors(EndpointMetaData.java:686)
org.jboss.ws.metadata.umdm.EndpointMetaData.initializeInternal(EndpointMetaData.java:567)
org.jboss.ws.metadata.umdm.EndpointMetaData.eagerInitialize(EndpointMetaData.java:553)
org.jboss.ws.metadata.builder.jaxws.JAXWSClientMetaDataBuilder.rebuildEndpointMetaData(JAXWSClientMetaDataBuilder.java:314)
org.jboss.ws.core.jaxws.spi.ServiceDelegateImpl.getPortInternal(ServiceDelegateImpl.java:271)
org.jboss.ws.core.jaxws.spi.ServiceDelegateImpl.getPort(ServiceDelegateImpl.java:202)
javax.xml.ws.Service.getPort(Service.java:143...
I've searched google long time but found nothing helpful topics. Some topics show examples accessing web-services from servlet, but unfortunately I can't do this...( And don't know what is cause of trouble.
Application server: jboss 4.2.3GA
Is it possible to connect web-service from servlet? How?
I've tried use #WebServiceRef annotation, but it seem web-container can't inject web-service stub. And I think that container must not do this itself, because stub classes have already been generated by wsimport tool, and its enouph to use this classes for accessing of web-service.
Stub classes were generated using the following command:
wsimport -keep -p com.myhost.ws http://www.myhost.com/services/MyWebService?wsdl
Did you make sure your classpath does not contain multiple JAX-B Jars with differing versions ? The exception looks like a version conflict to me. Application servers usually have some kind of "endorsed" lib directory that holds JARS that are always added in front of web application classpaths. Maybe your app server has a conflicting JAX-B implementation there ?
If you use Maven to package your application, make sure transitive dependencies don't pull in unwanted JAX-B Jars (use 'mvn dependency:tree' to check this).
This definitely sounds like a JAXB conflict to me. Check out the jaxb versions that you have in your war and make sure that they are not conflicting with a jaxb jar that Jboss may have in its lib directory.
Addytionally if jbossws-native library was installed correctly the following packages should be deleted from jboss_home/lib/endorsed directory:
jboss-jaxrpc.jar
jboss-jaxws-ext.jar
jboss-jaxws.jar
jboss-saaj.jar
Otherwise you don't have ability to connect to web service through EJB or servlet.

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