Create a single executable JAR from a Spring Based Java Application

Question

I have a spring based application that does a component/package scan looking for packages within a certain namespace. The application runs perfectly in Eclipse and I'd like to create a single executable JAR to deploy to our various environments.

I've tried various ways to get this to work but the only thing that's working is if I include the dependencies in a folder outside of the JAR. Here is what I have tried so far -

Maven Compile to a single jar from here , using this approach the single JAR is created with the dependencies included as classes. When running the JAR using -

“java –jar jarName.jar”

I get an error stating - "Error: Configuration problem: Unable to locate Spring NamespaceHandler for XML schema namespace http://www.springframework.org/schema/context]"
Using Export ‘As Runnable JAR file’ from Eclipse, and choose ‘Extract required libraries into generated JAR’ in the Library Handling section.

This also builds one jar with the dependencies as classes within it. When running the jar, I get the same “Error: Configuration problem: Unable to locate Spring NamespaceHandler for XML schema namespace [http://www.springframework.org/schema/context]”
Using Export ‘As Runnable JAR file’ from Eclipse, and choose ‘Package required libraries into generated JAR’ in the Library Handling section.

This builds one jar with the dependencies inside it as JARs (not classes). When I run this JAR I get the following error –

“Cannot search for matching files underneath URL [rsrc:com/company/] because it does not correspond to a directory in the file system java.io.FileNotFoundException: URL [rsrc:com/company/] cannot be resolved to absolute file path because it does not reside in the file system: rsrc:com/company/ at org.springframework.util.ResourceUtils.getFile(ResourceUtils.java:210”

So the JAR ran but was unable to do a scan for the components I was asking it to find.
Using Export ‘As Runnable JAR file’ from Eclipse, and choose ‘Copy required libraries into a sub-folder next to the generated JAR’ in the Library Handling section.

This creates a small JAR with a folder next to it which contains all of the dependencies as JARs. When I run this, everything works!

Therefore I don’t think it’s an issue with my code, there seems to be an issue with packaging spring that does a scan inside a single JAR. Would that be correct?

Does anyone have any advice on how to build a spring based application doing a package/component scan into a single runnable JAR?

ANSWER:

I added the following XML to my POM file and just used "mvn package", it created a single executable jar that worked. Why it worked is still a mystery.

      <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-shade-plugin</artifactId>
            <version>2.3</version>
            <executions>
                <execution>
                    <phase>package</phase>
                    <goals>
                        <goal>shade</goal>
                    </goals>
                    <configuration>
                        <transformers>
                            <transformer implementation="org.apache.maven.plugins.shade.resource.ManifestResourceTransformer">
                                <mainClass>com.company.project.MainApp</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>

Just use Spring Boot. The Spring Initializr can produce a minimal POM that will show you what you need. — chrylis -cautiouslyoptimistic-, Jan 28 '15 at 17:14

score 2 · Accepted Answer · answered Jan 28 '15 at 13:59

2

use Maven Shade Plugin for create uberjar. This could help you too.

answered Jan 28 '15 at 13:59

Cuzz

428
2
4
20

I've tried Maven Shade, it's effectively the same result as Option 1 above. – P456678 Jan 28 '15 at 14:25
Maven Shade did the trick in the end up, finding the correct transformer XML has taken me four days. Should be simpler than this! – P456678 Jan 28 '15 at 16:53
What was the problem? Reading the docs or have they be not clear enough? Or missing some kind of information? – khmarbaise Jan 29 '15 at 08:28
It's not creating an executable jar – Ajeesh Jan 19 '16 at 11:09

score 2 · Answer 2 · answered Feb 28 '15 at 15:22

I just had the very same problem than you today, with doing exactly the same steps :)

So thanks for your message, it makes me save some time and besides, i just want to quickly answer to your "Why it worked is still a mystery." sentence :

"This is because I have several Spring Jar in my dependencies. Some of the spring jars contain meta info files with the same name. To avoid that some meta files are overridden you have to merge it"

So this is why you need to add those two transformers to the maven snippet given into the Maven Shade Plugin documentation :

<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

source : http://robert-reiz.com/2011/11/14/832/

Hope it helps for understanding ;)

score 0 · Answer 3 · answered Mar 30 '16 at 13:39

0

try this one in eclipse: in the menu choose File -> Export -> Runnable JAR file

in the specification window:(after filling other blanks properly) Library handling : Select the second one

and Finish

now try the following command in cmd or terminal: java -jar [your project's name]

Hope it helps

answered Mar 30 '16 at 13:39

Farzan.s

945
8
9

I had no luck with that but it worked for me with the third option ("Copy required librarires into a sub-folder next to the generated JAR"). Then of course to run it I have to do it like this: java -cp my_project_lib/ -jar my_project.jar but that's ok with me. – Douglas Mendes Mar 02 '17 at 15:22

score 0 · Answer 4 · edited Jun 20 '20 at 09:12

0

You can use your option 1 Maven Compile to a single jar with additional goal parameters.

mvn clean package spring-boot:repackage

It will create the standalone jar file with Spring autoload functionality.

edited Jun 20 '20 at 09:12

Community

1
1

answered Oct 10 '17 at 10:06

M Kaweepatt Churcharoen

216
2
7

Create a single executable JAR from a Spring Based Java Application

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