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>

Answer 2

Instead of maven-shade-plugin use onejar-maven-plugin . One-JAR lets you package a Java application together with its dependency Jars into a single executable Jar file.

Answer 3

Yesterday I was encountered this issue too.

The solution was to prepare required files by manual concatenation and configuration of assembly plugin by this:

  <files>
    <file>
        <source>src/META-INF/spring.schemas</source>
        <outputDirectory>META-INF</outputDirectory>
    </file>
    <file>
        <source>src/META-INF/spring.handlers</source>
        <outputDirectory>META-INF</outputDirectory>
    </file>
  </files>
  <dependencySets>
    <dependencySet>
      <outputDirectory>/</outputDirectory>
      <useProjectArtifact>true</useProjectArtifact>
      <unpack>true</unpack>
      <scope>runtime</scope>
      <unpackOptions>
        <excludes>
            <exclude>META-INF/spring.handlers</exclude>
            <exclude>META-INF/spring.schemas</exclude>
        </excludes>
      </unpackOptions>  
    </dependencySet>
  </dependencySets>

NOTE: using one jar approach is not good enough - you can't be certain on hand mixed files, try to keep exporting of all dependence's as is...

Answer 4

assembly plugin have issues, use below plugin

<plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-shade-plugin</artifactId>
    <executions>
        <execution>
            <phase>package</phase>
            <goals>
                <goal>shade</goal>
            </goals>
            <configuration>
                <transformers>
                    <transformer implementation="org.apache.maven.plugins.shade.resource.ManifestResourceTransformer">
                        <mainClass>at.seresunit.lecturemanager_connector.App</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>
            </configuration>
        </execution>
    </executions>
</plugin>

you may get security exception resolve it using below configuration

 <configuration>
    <filters>
        <filter>
            <artifact>*:*</artifact>
            <excludes>
                <exclude>META-INF/*.SF</exclude>
                <exclude>META-INF/*.DSA</exclude>
                <exclude>META-INF/*.RSA</exclude>
            </excludes>
        </filter>
    </filters>
</configuration>

Answer 5

Have you tried the maven-assembly-plugin ?

It will create a single jar with dependencies for you and morevover it can make this jar be executable :

Use mainClass to specify the class you want to execute.

<plugin>
    <artifactId>maven-assembly-plugin</artifactId>
    <version>2.3</version>
    <configuration>
      <descriptorRefs>
        <descriptorRef>jar-with-dependencies</descriptorRef>
      </descriptorRefs>
      <archive>
        <manifest>
          <mainClass>org.sample.App</mainClass>
        </manifest>
      </archive>
    </configuration>
    <executions>
      <execution>
        <id>make-assembly</id> <!-- this is used for inheritance merges -->
        <phase>package</phase> <!-- bind to the packaging phase -->
        <goals>
          <goal>single</goal>
        </goals>
      </execution>
    </executions>
  </plugin>

Answer 6

For people who were hoping to find an answer for Spring Boot applications, all you need is:

<build>
    <plugins>
        <plugin>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-maven-plugin</artifactId>
        </plugin>
    </plugins>
</build>

Answer 7

I had the exact same problem after upgrading to Spring 6.0.0. My project has an assembly xml, and I fixed the spring.schemas and spring.handlers problem by adding the following handler to the <assembly> section:

<containerDescriptorHandlers>
    <containerDescriptorHandler>
        <handlerName>metaInf-spring</handlerName>
    </containerDescriptorHandler>
</containerDescriptorHandlers>

This is documented in https://maven.apache.org/plugins/maven-assembly-plugin/examples/single/using-container-descriptor-handlers.html