“unable to locate Spring NamespaceHandler” error

Question

I\'m creating a stand-alone Sava application with Spring, to handle the JDBC access. The application works fine on every test and I decided that I need a jar to be deployed

Answer 1

In addition to the solution posted by @GrampaJohn, I also had to make sure that I was packaging the required libraries into the generated JAR file instead of extracting them into the generated JAR.

In Eclipse Mars, after making changes to the pom.xml (added maven-shade plugin as suggested by @GrampaJohn), follow the steps:

File -> Export -> Select Java folder -> Runnable JAR File -> enter the Launch configuration (main file), export destination, and in Library Handling, select "Package required Libraries into generated JAR -> Click finish

.

Answer 2

Looks like a bug in the Maven Assembly Plugin - MASSEMBLY-360, and as discussed in this blog entry here.

In short, the meta-data files in the Spring JARs that handle the Spring namespaces are being mangled by maven.

Answer 3

I ran into this problem today with the maven-assembly-plugin. A search brought me to this question, and a look a the bug report suggested that perhaps I was using the wrong plugin. So I switched to the maven-shade-plugin. It works perfectly, as far as I can tell. I have an executable jar that incorporates a number of Spring modules as well as Apache MQ. Here's the relevant bit from my pom.xml:

<build>
<finalName>sample-broker</finalName>
<plugins>
  ...
  <plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-shade-plugin</artifactId>
    <version>2.0</version>
    <executions>
      <execution>
        <phase>package</phase>
        <goals>
          <goal>shade</goal>
        </goals>
        <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>
            <transformer implementation="org.apache.maven.plugins.shade.resource.ManifestResourceTransformer">
              <mainClass>org.XYZ</mainClass>
            </transformer>
          </transformers>
        </configuration>
      </execution>
    </executions>
  </plugin>
</plugins>
</build>

Answer 4

I found the error, the bug lies in an unfixed bug in the maven-assembly plugin. I used the following workaround:

First commented out the maven-assembly code in my pom. Then I copied the dependencies to a lib folder at the target using the maben-dependency-plugin:

<plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-dependency-plugin</artifactId>
    <executions>
        <execution>
            <id>copy-dependencies</id>
            <phase>package</phase>
            <goals>
                <goal>copy-dependencies</goal>
            </goals>
            <configuration>
                <outputDirectory>${project.build.directory}/lib</outputDirectory>
            </configuration>
        </execution>
    </executions>
</plugin>

Then I used the maven-jar-plugin to setup my executable jar:

        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-jar-plugin</artifactId>
            <version>2.3.1</version>
            <configuration>
                <archive>
                    <index>true</index>
                    <manifest>
                        <addClasspath>true</addClasspath>
                        <mainClass>org.foo.myproject.App</mainClass>
                    </manifest>
                    <manifestEntries>
                        <mode>development</mode>
                        <url>${pom.url}</url>
                        <key>value</key>

                    </manifestEntries>
                </archive>
            </configuration>
        </plugin>

Finally I created a bash script that is deployed with the application that runs my app with its libs and any provided arguments:

java -cp lib/*:myproject-0.0.1-SNAPSHOT.jar org.foo.myproject.App $@

I should have built the app in python =/

Answer 5

onejar-maven-plugin lets you resolve maven and spring contradiction by creating a single jar file with dependencies. It creates a wrapper around your jar file by placing it inside another jar (one-jar).

    <plugin>
            <groupId>org.dstovall</groupId>
            <artifactId>onejar-maven-plugin</artifactId>
            <version>1.4.4</version>
            <executions>
              <execution>
                <goals>
                    <goal>one-jar</goal>
                </goals>
              </execution>
            </executions>
        </plugin>
        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-jar-plugin</artifactId>
            <version>2.3.2</version>
            <configuration>
                <archive>
                    <manifest>
                        <mainClass>your.package.App</mainClass>
                    </manifest>
                </archive>
            </configuration>
        </plugin>

<!-- outside build tag in pom.xml -->
<pluginRepositories>
        <pluginRepository>
            <id>onejar-maven-plugin.googlecode.com</id>
            <url>http://onejar-maven-plugin.googlecode.com/svn/mavenrepo</url>
        </pluginRepository>
</pluginRepositories>