I am running into an issue with JAXB 2 when marshaling my objects. I have an XmlJavaTypeAdapter which is working perfectly fine in unit tests, but when I try to marshal the same object graph from a web service (using JAX-WS), the XmlJavaTypeAdapter is being ignored completely. What's the easiest way to debug this problem?
I have a simple standalone project checked into my svn repository that demonstrates this issue. Can somebody please take a look to see if I am doing something obviously wrong? The URL for the project is: http://archfirst.googlecode.com/svn/trunk/java/examples/jaxb-jaxws-sample. There is a readme.txt file in the root folder that describes the issue in detail.
Thanks.
Ok, I finally found the problem. My unit test was picking up the JAXB implementation in the Java runtime, whereas my web service was picking up the JAXB implementation from GlassFish. Apparently the implementation bundled with GlassFish (2.2.1.1) cannot handle my use case. I proved it by forcing my unit test to use jaxb-impl-2.2.1.1.jar. Also it seems that the bug has been fixed in the latest JAXB implementation (2.2.3-1), but I am struggling to figure out how to replace GlassFish's implementation with this new version (see my post here).
Related
I’m trying to use JAXB 2.2.11 in an osgi environment (Liferay DXP). I am having issues creating a JAXBContext. Based on some other sources found while researching like this and this, I have determined that in an osgi container I need to provide the correct classloader for JAXB to instantiate the context. So I have code like this:
ClassLoader cl package.with.jaxb.objects.ObjectFactory.class.getClassLoader();
JAXBContext jc = JAXBContext.newInstance("package.with.jaxb.objects ", cl);
This code causes a null pointer exception with the following stack trace:
Caused by: java.lang.NullPointerException
at javax.xml.bind.ContextFinder.handleClassCastException(ContextFinder.java:129)
at javax.xml.bind.ContextFinder.newInstance(ContextFinder.java:201)
at javax.xml.bind.ContextFinder.newInstance(ContextFinder.java:146)
at javax.xml.bind.ContextFinder.find(ContextFinder.java:371)
at javax.xml.bind.JAXBContext.newInstance(JAXBContext.java:446)
at javax.xml.bind.JAXBContext.newInstance(JAXBContext.java:409)
Looking at the source for ContextFinder I can see that context must be null on line 129:
throw handleClassCastException(context.getClass(), JAXBContext.class);
I thought perhaps the problem was that my module has a dependency on jaxb-api 2.2.11 but the jaxb-impl classes are provided by rt.jar at runtime and are probably newer than 2.2.11 because Liferay DXP runs on JDK 1.8. To get around this issue, I have tried including jaxb-impl.jar 2.2.11 as a dependency in my osgi module, thinking then the jaxb-api & jaxb-impl versions would match. After that, trying to create a JAXBContent using the same code as above results in the following error:
ClassCastException: attempting to cast jar:file:/C:/Program%20Files/Java/jdk1.8.0_144/jre/lib/rt.jar!/javax/xml/bind/JAXBContext.class to bundleresource://623.fwk616113009:13/javax/xml/bind/JAXBContext.class. Please make sure that you are specifying the proper ClassLoader.
By the looks of this message, the JAXBContext that is getting instantiated is from the version of JAXBContext that is loaded via rt.jar. This is very confusing to me because I would expect the version of JAXBContext loaded by my module’s classloader to be used since I’ve included jaxb-impl.jar in my module and I’ve specified my module’s classloader is the one to be used in my call to JAXBContext.newInstance. Can anyone shed some light on how I can get jaxb 2.2.11 to work in an osgi container?
*Please note that I can’t upgrade the version of jaxb-api used by my module because the JAXB code is actually in a 3rd party jar that requires jaxb 2.2.11 (I have just eliminated the 3rd party jar from the equation for now by writing some test JAXB code).
After extensive research I found the following solution. Since it seemed like passing the bundle class loader as suggested by the accepted answer in this post had to be correct, I followed the path of figuring out why I was getting a NullPointerException when I tried that. After carefully looking over the source code for jaxb-api to follow the stack trace of the NullPointerException, I could see that the jaxb-api code does things like
classLoader.loadClass("com.sun.xml.internal.bind.v2.ContextFactory")
where classLoader is my bundle's class loader (since that's what I passed in) and ContextFactory is actually a class in jaxb-impl which is loaded by the bootstrap class loader. This is where the problem lies because my
bundle's classloader isn't going to be able to see classes loaded by the bootstrap class loader. This threw me for a while because I'm not used to how class loaders work in osgi. I incorrectly was thinking the classes loaded by the bootstrap class loader would be visible because I'm used to web app class loading where there is delegation. In osgi class loaders
are completely isolated from each other, things are only visible if they are exported. To get around the issue I found some helpful posts talking about similiar issues. It turns out there is a concept
called boot delegation in osgi where you can specify a list of classes/packages to always be loaded via the bootstrap classloader. So the end result is two steps:
1) Switch the thread's class loader to your bundle class loader before calling the code to get the JAXBContext:
ClassLoader currentClassLoader = Thread.currentThread().getContextClassLoader();
try {
// ObjectFactory here is in the same package as my classes to be marshalled
ClassLoader objectFactoryClassLoader = ObjectFactory.class.getClassLoader();
Thread.currentThread().setContextClassLoader(objectFactoryClassLoader);
// JAXB code goes here
} finally {
Thread.currentThread().setContextClassLoader(currentClassLoader);
}
2) Specify packages to be loaded using the boot delegation mechanism. This list needs to include the transitive dependencies of the classes you need loaded. In my case, I'm using Liferay so the list
is specific to Liferay and it goes in portal-ext.properties configuration file. Luckily I found this post where someone had done most of the work for me:
module.framework.properties.org.osgi.framework.bootdelegation=\
__redirected,\
com.liferay.aspectj,\
com.liferay.aspectj.*,\
com.liferay.portal.servlet.delegate,\
com.liferay.portal.servlet.delegate*,\
com.sun.ccpp,\
com.sun.ccpp.*,\
com.sun.crypto.*,\
com.sun.image.*,\
com.sun.jmx.*,\
com.sun.jna,\
com.sun.jndi.*,\
com.sun.mail.*,\
com.sun.management.*,\
com.sun.media.*,\
com.sun.msv.*,\
com.sun.org.*,\
com.sun.syndication,\
com.sun.tools.*,\
com.sun.xml.*,\
com.yourkit.*,\
org.eclipse.persistence.internal.jaxb,\
org.eclipse.persistence.internal.jaxb.*,\
javax.xml.*,\
sun.*
Helpful links:
Why can't JAXB find my jaxb.index when running inside Apache Felix?
What is the difference between bootdelegation and DynamicImport-Package in osgi
https://web.liferay.com/web/user.26526/blog/-/blogs/liferay-dxp-and-weblogic-
https://dev.liferay.com/develop/tutorials/-/knowledge_base/7-0/bundle-classloading-flow
http://apache-felix.18485.x6.nabble.com/Classloading-for-JAXB-td4834670.html
Here is the workaround that worked for me using JDK 11, Liferay DXP/7.2, OSGI, with a sample Jax-RS web service created from Dev Studio. The error I was getting was as follows when trying to access the web service:
JAXBException occurred : Implementation of JAXB-API has not been found
on module path or classpath..
com.sun.xml.internal.bind.v2.ContextFactory cannot be found by
org.apache.aries.jax.rs.whiteboard_1.0.4.
What worked for me was to define the context factory at the system level to override the predefined context factory. Add the following system variable to your system
javax.xml.bind.JAXBContextFactory=com.sun.xml.bind.v2.ContextFactory
For example you can add this in your setenv.sh/bat file in Tomcat, or in eclipse you can access your server Launch Configuration, Arguments tab, under VM arguments
-Djavax.xml.bind.JAXBContextFactory=com.sun.xml.bind.v2.ContextFactory
This worked without adding any extra libraries since Liferay already has those libraries included.
How does this work? Refer to the javadoc for JaxBContext and read the Discovery of JAXB implementation Section. Using the /META-INF/services/javax.xml.bind.JAXBContext file did not work for me.
I hope this helps someone.
One final note for DXP users, if you get a permission denied on your service then you need to read about Service Access Policies
The best place to see how it should be done is Apache Karaf. It doesn't install any JAXB-API bundle - instead it uses org.apache.servicemix.specs.jaxb-api-2.2-2.7.0.jar inside lib/endorsed directory.
This way you won't use JAXB-API provided by rt.jar.
For implementation - it's best to use ServiceMix version of JAXB bundles:
org.apache.servicemix.bundles:org.apache.servicemix.bundles.jaxb-impl:2.2.11_1
org.apache.servicemix.bundles:org.apache.servicemix.bundles.jaxb-xjc:2.2.11_1
It seems that when I reference AutoMapper v3.1.0 in my Xamarin.iOS project, the build fails with this error message:
Error MT2002: Failed to resolve "System.Linq.Expressions.Expression System.Linq.Expressions.ExpressionVisitor::Visit(System.Linq.Expressions.Expression)" reference from "System.Core, Version=2.0.5.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e" (MT2002)
When I roll back to the revision before I added this, it all works fine.
Unfortunately, I've already done quite a bit of work with AutoMapper in my unit tests and it would be problematic to remove it now. I guess that's a lesson to learn: just because it works in a test doesn't mean it works in Xamarin.iOS.
I would be very grateful if anyone has any ideas.
Edit: I have now discovered a MonoTouch directory in the AutoMapper package, but referencing the AutoMapper.dll and AutoMapper.iOS.dlls found within does not solve the problem.
Edit #2: This issue only occurs when building for the device - I guess the MSIL to native converter doesn't like AutoMapper for some reason. I'm trying to find a way to "hint" to this compiler that we need these symbols, which is what I think the purpose of the LinkerPleaseInclude.cs file is.
This issue is temporarily resolved - I had to hack out the offending symbols in AutoMapper and recompile it. Please see automapper issue #429 for more information on what symbols I removed. Until AutoMapper is updated to fix this problem, that's how you have to solve it for now.
The reason for this is explained concisely in another StackOverflow question - basically there are subtle differences between the .NET and Mono frameworks that in this case are incompatible with AutoMapper.
This answer previously stated that you should turn off linking to work with AutoMapper. While you can do this for development, it's not suitable for production use as it will yield a massive binary and you will not be able to submit your app to the app store.
Is there any alternative to achieving serialising and deserialising of objects in Xamarin.iOS (Monotouch) using protobuf-net other than this method:
http://www.frictionpointstudios.com/blog/2011/3/31/using-protobuf-net-serialization-in-unity-iphone.html
Reading around some people claim they have managed it (without giving evidence), but my understanding is that [iOS JIT==NO] so does not quite make sense.
If the only possible solution is to fully AOT all relevant classes what might a suitable pre/post-build event command line be to perform this AOT for any relevant assemblies automatically?
I've heard a good number of people have success via that route, but I too can't give documented evidence.
That method is a bit out of date - I've simplified a few steps; there is a standalone pre-compile tool that should work:
create a project/assembly for the DTOs that you want to serialize that references the appropriate version of protobuf-net; presumably CoreOnly/ios, ideally with that dll set to copy into the output directory (it just makes life easier)
run
precompile "SomePath/YourDto.dll" -t:MySerializer -o:MySerializer.dll
(maybe with a mono before that to get mono to host the exe)
this should resolve the framework and compile a MySerializer.dll that you can reference, which involves zero JIT (MySerializer.dll will reference your dto dll and the version of protobuf-net that your dto dll referenced)
now reference your dto dll, the serializer dll, and the protobuf-net dll, and it should all work just by using new MySerializer().Serialize(...)
when you compile your solution, the projects should all AOT nicely
I'll be happy to offer guidance, but currently I am mac-less, so I can't check right now. If you get any problems let me know. If it can't resolve the framework, you can add -f:{path to the framework assemblies} to give it a clue.
I got protobuf-net 2 working on Xamarin-iOS by using the netstandard1.0 dll. You can get this dll by extracting the nuget package. No changes were needed.
Related to Access restriction on class due to restriction on required library rt.jar? jaxb-impl has many classes that are provided by rt.jar, which is the reason behind the warning.
I generated my web service from a WSDL file.
If I'm meant to exclude jaxb-impl in order to get rid of the warning, what is it for then?
Which are the libraries I really need to keep for my web service to run, and which were only useful for generating the code related to it?
jaxb-impl is the JAXB implementation that CXF will use by default. In most cases, you can remove it at runtime (not at wsdl2java time though) and CXF will be ok. However, the jaxb-impl that CXF pulls in is generally newer than the versions found in the JDK and usually has several bugs fixed that would still be present in the in-JDK versions of JAXB. CXF and CXF users tend to stress JAXB pretty hard and find interesting issues that we log with them and eventually get fixed.
I'm building an application with (smart)gwt, hibernate (actually gilead, or hibernate4gwt) and Spring Security.
I'm pretty new to all of these, by the way.
Everything worked fine until now, but I've recently added Spring security functionality, in order to implement an authentication system. Seems there are multiple ways of making this work, I looked at a few tutorials.
I liked this simple idea here: http://blog.maxmatveev.com/2011/06/gwt-and-spring-security-integration-as.html?showComment=1328698687249#c4823182825437196300
I also tried this one (a lot of dummy classes and such, but oh well): http://seewah.blogspot.com/2009/02/gwt-and-spring-security.html
In both cases I have the same problem, I get this error in the applicationContext.xml:
Error occured processing XML 'org/springframework/security/access/intercept/aopalliance/MethodSecurityInterceptor'
In the first link it occurs at line:
<security:global-method-security secured-annotations="enabled" mode="aspectj"/>
In the second link it occurs at line:
<security:global-method-security secured-annotations="enabled" jsr250-annotations="disabled" />
I googled the problem, but I didn't find an answer..
PS1: using Eclipse 3.6, and I have installed plugins for Spring framework and aspectJ.
PS2: I didn't write all the code here, instead I liked to the tutorials i used (would have been too much code).
Maybe someone can help me out.
Thank you in advance.
It may be a problem with version of Spring/Spring Security.
Make sure you are updated to recent version (to handle attribute mode="aspectj" of element security:global-method-security) e.g. Spring-Security 3.1.