Spring with maven-shade-plugin - spring

I am trying to use to versions of spring in the same application: the first one is a webapp with spring 2.6 and the second it a jar client, with spring 4.0.2. The client communicates with another application and will be a dependency for the webapp. The problem is that the classloader will just load one time the common classes from spring and it will certainly fail.
I tried to use ElasticSearch aproach of using shaded dependencies(maven shade plugin) and relocate spring from the client to a different package (from org.springframework to my.springframework) and the uber jar seems to be constructed fine.
The issue is that Spring is based on spring.schemas and spring.handlers for validating xml config files and loads this files from classpath (META-INF folder and this paths are hardcoded in Spring code - e.q. PluggableSchemaResolver). I modified this files to point from org.srpingframework to my.springframework.
At runtime it seems that the classloader reads these files from the webapp, which has this files but with the real spring path and the exception is something like
org.realsearch.springframework.beans.FatalBeanException: Class [org.springframework.context.config.ContextNamespaceHandler] for namespace [http://www.springframework.org/schema/context] does not implement the [my.springframework.beans.factory.xml.NamespaceHandler] interface.
To me it seems that is impossible to achieve what I am trying (use tho spring versions in the same application with one of them relocated). Any ideas here? Am I wright?:d

Related

Spring Boot JarFileSystem for wrapped JARs

I've got a Spring Boot application packaged as an Uber JAR. One of the wrapped JARs has logic within it to utilize a Java FileSystem for walking a resource tree that is embedded in that particular JAR file.
Unfortunately, this statement appears to be true:
Now opening jar files isn't a big deal. Esp with the introduction of the JarFileSystem. However Spring Boot includes jar files inside their jars. There is currently no support for that. You can't create a JarFileSystem inside a JarFileSystem.
With that being said, Spring Boot has a fair amount of handling surrounding it's wrapped JARs:
JarURLConnection
Everything else under org/springframework/boot/loader/jar
However, there doesn't appear to be any mechanism for registering Spring Boot's approach as a FileSystemProvider...
org.springframework.boot.loader.LaunchedURLClassLoader unable to load 3rd party FileSystemProvider implementation from spring boot executable JAR seemed like a similar problem, but didn't appear to be directly related.
Has anyone had any luck creating a FileSystem for one of Spring Boot's wrapped JARs?

Unable to load Spring Framework Libraries in Wildfly accessible to deployed JAR

I am writing a custom Keycloak User Storage SPI, which is JAR file. I would like to use Spring DI in the JAR. I have added Spring JARs as Modules in Keycloak's Wildfly server.
Also, not able to load Spring context as Keycloak User Storage SPI initiate from META-INF.services "org.keycloak.storage.UserStorageProviderFactory" and invokes UserStorageProviderFactory.init method.
It also doesn't read the properties file inside resources directory.
Please advise how can I make this work.
May be, there would be workaround by using .ear file with your jar wrapped into it. If you are using maven then you can reside all required spring dependencies in that pom of your jar.
For further reference, you can go to this git link which might be related to what you are doing.
https://github.com/thomasdarimont/keycloak-user-storage-provider-demo

Prevent SpringBoot from creating an EmbeddedServletContainer

I'm trying to convert an existing spring application into a spring boot application. this application is not a web application but somewhere deep in it's maven dependencies hierarchy it includes a spring-web jar and therefore spring-boot tries to autoconfigure a WebEnvironment and in turn complains about not finding an EmbeddedServletContainerFactory. But this is intended as I'm using spring-boot-starter instead of spring-boot-starter-web.
My questing is: how can I prevent spring-boot from autodiscovering web specific items in the classpath? I already tried something like
#EnableAutoConfiguration(exclude = { EmbeddedServletContainerAutoConfiguration.class })
but it doesn't seem to work. Debugging the startup process I see that it runs into a method called deduceWebEnvironment() which is called unconditionally. This method returns true as soon as the following classes are on the classpath:
javax.servlet.Servlet, org.springframework.web.context.ConfigurableWebApplicationContext
But again, even this classes exist in the cp, I don't want to startup a web-application.
Try new SpringApplicationBuilder(YourApp.class).setWebEnvironment(false).run(args) You can also disable the web mode via configuration in application.properties
spring.main.web-environment=false
See the documentation

Classloader issue on Mule server

I am running my application on mule server. Mule server has there own sets of jars and my application that is running on mule server also has few jars. While working on Spring batch I found that JettisonMappedXmlDriver class exists in my application xstream jar as well as mule server jar as well. This class internally refer MappedXMLOutputFactory class that is in jettision jar which is also in my application but some how I am getting classnotfound error for MappedXMLOutputFactory class. This looks like class-loader issue.
If I add jettision jar in mule server then everything work fine but, I can't add this jar on my production environment. Can some body tell me how do I force to load the class from my application jettision jar file. It looks weird to me as classloader should have load MappedXMLOutputFactory class from jettision jar that is in my application folder like it is doing for other classes.
Please let me know if anybody found such issue.
The Mule application classloader is configurable: http://www.mulesoft.org/documentation/display/current/Classloader+Control+in+Mule
So just configure your application's classloader to first look at the JARs it embeds in /lib before deferring to the Mule System classloader.
You will encounter this issue if you have multiple versions of the same class in differnet jars, albeit with different method signatures. The ClassNotFound Error is usually not the only exception that occurs, you will often see another one before that, typically a "NoSuchMethodException" which forces class loader to unload the offending class.
I would suggest using maven or gradle to assemble your application and then use the dependency:tree target to query version conflicts.

Initialize Spring Application Context for spring projects packaged as a jar

We have several java projects. Most of them are built with Struts 2.0 framework and few built with Spring 3.2. We want to consolidate all the back-end integration service into a separate project using spring 3.2 and import this jar file on all the projects. Here are my questions
What is the best way to initialize spring application-context for a jar based spring project? This jar is utilized by multiple web-project that are built using Struts and other non spring MVC frameworks.
I read How to package spring based library for reuse?. However, this question didn't answer on how to auto-load the application context when you a call a Service from the built spring-example.jar file.
For example. I have a WeatherService.java class in spring-framework.jar file. I want to import the spring-framework.jar file into another Struts-MVC based application and call WeatherService.java from an Action Class. I want the spring bean configuration to initiate automatically when calling the WeatherService.
You can use #Import annotation if using Java configurations or <import> tag if using XMl configs. With this approach you can reuse import one Spring context into another one.
Link to documentation:
http://docs.spring.io/spring/docs/current/spring-framework-reference/htmlsingle/#beans-java-using-import
EDIT:
If you are using maven, place your application-context.xml into src/main/resources. If not, make sure that it's on classpath.
Than if you are using XML config do
<import resource="classpath:application-config.xml"/>
or if you are using Java config do
#ImportResource("classpath:application-config.xml")

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