How to create spring-based executable jar with maven?

Question

I have a Maven based Spring-WS client project that I want to package as a single jar. In eclipse, everything runs properly. When I try to package it as an executable jar, I get ClassNotFound exceptions since the Spring jars are not included in my application jar.

So I added the maven-shade-plugin to include all my dependencies in my application jar. When I look at my app jar, I see all the class files from all the dependencies included (all the library jar's are exploded).

<build>
    <plugins>
        <plugin>
            <artifactId>maven-compiler-plugin</artifactId>
            <configuration>
                <source>1.6</source>
                <target>1.6</target>
            </configuration>
        </plugin>

        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-jar-plugin</artifactId>
            <version>2.4</version>
            <configuration>
                <archive>
                    <manifest>
                        <addClasspath>true</addClasspath>
                        <mainClass>com.cws.cs.Client</mainClass>
                    </manifest>
                </archive>
            </configuration>
        </plugin>

        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-shade-plugin</artifactId>
            <version>1.7</version>
            <executions>
                <execution>
                    <phase>package</phase>
                    <goals>
                        <goal>shade</goal>
                    </goals>
                </execution>
            </executions>

        </plugin>
    </plugins>
</build>

My problem is that in the packaging process, my multiple spring dependencies have different META-INF/spring.schemas files that override each other. Consequently, my final jar has an incomplete spring.schemas file.

So when I try to run my executable jar, I get Spring error messages that files cannot be found since the spring.schemas file is incomplete (the Spring-WS's jar has overriden the Spring-core's spring.schemas file).

My executable jar's META-INF/spring.schemas:

http\://www.springframework.org/schema/web-services/web-services-1.5.xsd=/org/springframework/ws/config/web-services-1.5.xsd
http\://www.springframework.org/schema/web-services/web-services-2.0.xsd=/org/springframework/ws/config/web-services-2.0.xsd
http\://www.springframework.org/schema/web-services/web-services.xsd=/org/springframework/ws/config/web-services-2.0.xsd

Instead of Spring-beans.jar META-INF/spring.schemas:

http\://www.springframework.org/schema/beans/spring-beans-2.0.xsd=org/springframework/beans/factory/xml/spring-beans-2.0.xsd
http\://www.springframework.org/schema/beans/spring-beans-2.5.xsd=org/springframework/beans/factory/xml/spring-beans-2.5.xsd
http\://www.springframework.org/schema/beans/spring-beans-3.0.xsd=org/springframework/beans/factory/xml/spring-beans-3.0.xsd
http\://www.springframework.org/schema/beans/spring-beans-3.1.xsd=org/springframework/beans/factory/xml/spring-beans-3.1.xsd
http\://www.springframework.org/schema/beans/spring-beans.xsd=org/springframework/beans/factory/xml/spring-beans-3.1.xsd
http\://www.springframework.org/schema/tool/spring-tool-2.0.xsd=org/springframework/beans/factory/xml/spring-tool-2.0.xsd
http\://www.springframework.org/schema/tool/spring-tool-2.5.xsd=org/springframework/beans/factory/xml/spring-tool-2.5.xsd
http\://www.springframework.org/schema/tool/spring-tool-3.0.xsd=org/springframework/beans/factory/xml/spring-tool-3.0.xsd
http\://www.springframework.org/schema/tool/spring-tool-3.1.xsd=org/springframework/beans/factory/xml/spring-tool-3.1.xsd
http\://www.springframework.org/schema/tool/spring-tool.xsd=org/springframework/beans/factory/xml/spring-tool-3.1.xsd
http\://www.springframework.org/schema/util/spring-util-2.0.xsd=org/springframework/beans/factory/xml/spring-util-2.0.xsd
http\://www.springframework.org/schema/util/spring-util-2.5.xsd=org/springframework/beans/factory/xml/spring-util-2.5.xsd
http\://www.springframework.org/schema/util/spring-util-3.0.xsd=org/springframework/beans/factory/xml/spring-util-3.0.xsd
http\://www.springframework.org/schema/util/spring-util-3.1.xsd=org/springframework/beans/factory/xml/spring-util-3.1.xsd
http\://www.springframework.org/schema/util/spring-util.xsd=org/springframework/beans/factory/xml/spring-util-3.1.xsd

I'm stumped. I am not sure if/how I can package everything as a single executable jar. I don't know if this is a shade-plugin configuration issue, or if I am trying to do something impossible. It would not seem correct that I would have to manually create my own spring.schemas file (a concatenation of the others).

I may have jumped the gun a little. In digging up more info on the shade plugin, I noticed the AppendingTransformer that I had previously missed. However, my concern is how to know which other files are having the same problems? I've discovered/caught this particular Spring issue. I have no idea about any other libraries that may be doing something similar...

Any suggestions would be appreciated.

Answer 1

You can add the following configuration so that the contents of the .schema files from all the jars get appended together.

<configuration>
  <transformers>
    <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>
</configuration>