Develop Reference

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.

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 :).

Tomcat 6 Showing error after including glassfish 3 severs jar file in tomcat

On my local system i am using glassfish server 3.0. I have included all servers jar file of glassfish3 on my actual server that is having Tomcat6.
That is showing now following Exceptions:
HTTP Status 500 -
--------------------------------------------------------------------------------
type Exception report
message
description The server encountered an internal error () that prevented it from fulfilling this request.
exception
org.apache.jasper.JasperException: /pages/login.jsp(178,36) The s:form tag declares that it accepts dynamic attributes but does not implement the required interface
org.apache.jasper.compiler.DefaultErrorHandler.jspError(DefaultErrorHandler.java:40)
org.apache.jasper.compiler.ErrorDispatcher.dispatch(ErrorDispatcher.java:407)
org.apache.jasper.compiler.ErrorDispatcher.jspError(ErrorDispatcher.java:148)
org.apache.jasper.compiler.Validator$ValidateVisitor.visit(Validator.java:775)
org.apache.jasper.compiler.Node$CustomTag.accept(Node.java:1507)
org.apache.jasper.compiler.Node$Nodes.visit(Node.java:2338)
org.apache.jasper.compiler.Node$Visitor.visitBody(Node.java:2388)
org.apache.jasper.compiler.Node$Visitor.visit(Node.java:2394)
org.apache.jasper.compiler.Node$Root.accept(Node.java:489)
org.apache.jasper.compiler.Node$Nodes.visit(Node.java:2338)
org.apache.jasper.compiler.Validator.validate(Validator.java:1737)
org.apache.jasper.compiler.Compiler.generateJava(Compiler.java:178)
org.apache.jasper.compiler.Compiler.compile(Compiler.java:306)
org.apache.jasper.compiler.Compiler.compile(Compiler.java:286)
org.apache.jasper.compiler.Compiler.compile(Compiler.java:273)
org.apache.jasper.JspCompilationContext.compile(JspCompilationContext.java:566)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:317)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:320)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:266)
javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter.doFilter(StrutsPrepareAndExecuteFilter.java:88)
How to resolve this problem.
While deploying war file i am having following jar file included in my war file(from glashfish server)
bean-validator.jar
commons-fileupload-1.2.1.jar
commons-io-1.3.2.jar
commons-logging-1.0.4.jar
freemarker-2.3.15.jar
javax.annotation.jar
jaxr-api-osgi.jar
jaxpc-api-osgi.jar
jsf-api.jar
jsf-impl.jar
jstl-impl.jar
mysql-connector-java-5.1.14-bin.jar
ongl-2.7.3.jar
struts2-core-2.1.8.1.jar
struts2-jquery-plugin-1.8.3.jar
webservices-api-osgi.jar
weld-osgi-bundle.jar
xwork-core-2.1.6.jar
javax.ejb.jar
javax.enterprise.deploy.jar
javax.jms.jar
javax.mail.jar
javax.management.j2ee.jar
javax.persistence.jar
javac.resource.jar
javax.security.auth.message.jar
javax.security.jacc.jar
javax.servlet.jar
javax.servlet.jsp.jar
javax.servlet.jsp.jstl.jar
javax.transaction.jar

Ideally our Enterprise Applications should be independent of any Server we use. Hence all the servers have a lib folder where you can put any specific JARs required in that environment.
I would recommend you to remove the glassfish JARS from your project and place them in your local glasshfish server's lib (if they are not already there). Alternatively you can place the JARs in a differen folder and add that folder to classpath.
As per the stacktrace posted by you there is a conflict in the JARs... Since you have tomcat and glassfish, both jars on your actual server, when it loads the application it is loading Tag classes from wrong JAR for the taglib it is picking. Hence it is recommended to have only one JAR.

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