Spring Framework and uber-jar made by maven-shade-plugin

If you’re trying to build a Java application in a form of an uber-jar with use of Spring Framework, maven and maven-shade-plugin and you see an error similar to the below one (BeanDefinitionParsingException: Configuration problem: Unable to locate Spring NamespaceHandler for XML schema namespace) after running the application then this article is for you.

org.springframework.beans.factory.parsing.BeanDefinitionParsingException: Configuration problem: Unable to locate Spring NamespaceHandler for XML schema namespace [http://www.springframework.org/schema/context]
Offending resource: class path resource [app-context.xml]

	at org.springframework.beans.factory.parsing.FailFastProblemReporter.error(FailFastProblemReporter.java:70)
	at org.springframework.beans.factory.parsing.ReaderContext.error(ReaderContext.java:118)
	at org.springframework.beans.factory.parsing.ReaderContext.error(ReaderContext.java:110)
	at org.springframework.beans.factory.xml.BeanDefinitionParserDelegate.error(BeanDefinitionParserDelegate.java:301)
	at org.springframework.beans.factory.xml.BeanDefinitionParserDelegate.parseCustomElement(BeanDefinitionParserDelegate.java:1407)
	at org.springframework.beans.factory.xml.BeanDefinitionParserDelegate.parseCustomElement(BeanDefinitionParserDelegate.java:1400)
	at org.springframework.beans.factory.xml.DefaultBeanDefinitionDocumentReader.parseBeanDefinitions(DefaultBeanDefinitionDocumentReader.java:172)
	at org.springframework.beans.factory.xml.DefaultBeanDefinitionDocumentReader.doRegisterBeanDefinitions(DefaultBeanDefinitionDocumentReader.java:142)
	at org.springframework.beans.factory.xml.DefaultBeanDefinitionDocumentReader.registerBeanDefinitions(DefaultBeanDefinitionDocumentReader.java:94)
	at org.springframework.beans.factory.xml.XmlBeanDefinitionReader.registerBeanDefinitions(XmlBeanDefinitionReader.java:508)
	at org.springframework.beans.factory.xml.XmlBeanDefinitionReader.doLoadBeanDefinitions(XmlBeanDefinitionReader.java:392)
	at org.springframework.beans.factory.xml.XmlBeanDefinitionReader.loadBeanDefinitions(XmlBeanDefinitionReader.java:336)
	at org.springframework.beans.factory.xml.XmlBeanDefinitionReader.loadBeanDefinitions(XmlBeanDefinitionReader.java:304)
	at org.springframework.beans.factory.support.AbstractBeanDefinitionReader.loadBeanDefinitions(AbstractBeanDefinitionReader.java:181)
	at org.springframework.beans.factory.support.AbstractBeanDefinitionReader.loadBeanDefinitions(AbstractBeanDefinitionReader.java:217)
	at org.springframework.beans.factory.support.AbstractBeanDefinitionReader.loadBeanDefinitions(AbstractBeanDefinitionReader.java:188)
	at org.springframework.web.context.support.XmlWebApplicationContext.loadBeanDefinitions(XmlWebApplicationContext.java:125)
	at org.springframework.web.context.support.XmlWebApplicationContext.loadBeanDefinitions(XmlWebApplicationContext.java:94)
	at org.springframework.context.support.AbstractRefreshableApplicationContext.refreshBeanFactory(AbstractRefreshableApplicationContext.java:129)
	at org.springframework.context.support.AbstractApplicationContext.obtainFreshBeanFactory(AbstractApplicationContext.java:614)
	at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:515)
	...

Solution

The solution is to extend maven-shade-plugin configuration in your pom.xml as given in documentation for maven-shade-plugin Resource Transformers. The important part to add is:

<transformer implementation="org.apache.maven.plugins.shade.resource.AppendingTransformer">
    <resource>META-INF/spring.handlers</resource>
</transformer>
<transformer implementation="org.apache.maven.plugins.shade.resource.AppendingTransformer">
    <resource>META-INF/spring.schemas</resource>
</transformer>

The complete configuration of maven-shade-plugin is therefore something like this:

<plugin>
	<groupId>org.apache.maven.plugins</groupId>
	<artifactId>maven-shade-plugin</artifactId>
	<version>3.1.0</version>
	<executions>
	    <execution>
		<phase>package</phase>
		<goals>
		    <goal>shade</goal>
		</goals>
		<configuration>
		    <createDependencyReducedPom>false</createDependencyReducedPom>
		    <transformers>
		        <transformer implementation="org.apache.maven.plugins.shade.resource.ManifestResourceTransformer">
		            <mainClass>fully.qualified.your.main.class</mainClass>
		        </transformer>
		        <transformer implementation="org.apache.maven.plugins.shade.resource.AppendingTransformer">
		            <resource>META-INF/spring.handlers</resource>
		        </transformer>
		        <transformer implementation="org.apache.maven.plugins.shade.resource.AppendingTransformer">
		            <resource>META-INF/spring.schemas</resource>
		        </transformer>
		    </transformers>
		    <filters>
		        <filter>
		            <artifact>*:*</artifact>
		            <excludes>
		                <exclude>META-INF/*.SF</exclude>
		                <exclude>META-INF/*.DSA</exclude>
		                <exclude>META-INF/*.RSA</exclude>
		            </excludes>
		        </filter>
		    </filters>
		</configuration>
	    </execution>
	</executions>
</plugin>

The above worked for me. Parameters <filters> and <createDependencyReducedPom/> were accompanying some sample plugin configuration I found and they’re not breaking things in my case.