EWM/RTC Plain Java Client Libraries and Maven


I have worked with Maven applications using the RTC Plain Java Client libraries often recently. It has not always been fun, I have been struggling with Maven. I have been struggling with the Plain Java Client Libraries and Maven interacting. In this bog, I will try to share some things I have learned over the time, and recently, that you can use when working with Maven, especially in the context of EWM/RTC automation using the Plain Java Client Libraries.

Maven basics

How to install Maven is documented in this link. I do not intent to rewrite this documentation. I just want to emphasize some things that I always run into.

  1. Using Maven, requires a Java JDK. A JRE is not sufficient. Where to download a valid, supported, IBM JDK, is explained below.
  2. When using Maven in the command line, make sure to have the JAVA_HOME set to the correct JDK.
  3. When using Maven in the command line, make sure to have Maven added to the path.
  4. When using Maven with the Eclipse IDE, make sure to have an up to date Maven installed. I usually download the recent version, install it to work with a command line and then add that install to Eclipse.
  5. When using Maven with the Eclipse IDE, there is still the need to have a compatible JDK configured. Make sure to go to Preferences>Java>Installed JRE’s, add the JDK and set it as active. Then go to Preferences>Java>Installed JRE’s>Execution Environments configure an environment with the JDK. E.g. JavaSE-1.8 for EWM 7.0.x.
  6. When using Maven for a project in an Eclipse IDE right click on the project
    1. Use Maven>Update Project to make sure Eclipse is configured correctly.
    2. Use Run As>Maven clean on the Project or the pom.xml.
    3. Use Run As>Maven install on the Project or the pom.xml.
    4. Sometimes the Eclipse build mechanism seems to be in conflict with Maven, Project>Clean might help.
  7. Sometimes weird things happen. Run maven with -e or -X to see more details.
  8. Sometimes weird things happen, if all fails, consider to delete the local repository folder in the .m2 folder in your user directory.

Maven and the EWM Plain Java client libraries

When working with EWM/RTC automation based on the plain java client libraries, it is possible to download a valid, supported, IBM JDK on the same page where the Plain Java Client Libraries are hosted. When working with EWM/RTC and the Plain Java Client Libraries, the items below show the most important files to download to work with the Plain Java Client Libraries. To get them go to the All downloads tab for the version required. As an example for EWM 7.0.2 go to https://jazz.net/downloads/workflow-management/releases/7.0.2?p=allDownloads.

  1. Get the 10-Free Developers License Activation Kit. Scroll down to the section License Keys and download the 10-Free Developers License Activation Kit. It is very useful to run EWM test systems.
  2. Get the Client for Eclipse. Scroll to the Plain .zip Files section. Download the Client for Eclipse for your architecture.
  3. Get the plain Java Client Libraries. In the Plain .zip Files section download the Plain Java Client Libraries and the API documentation.
All Downloads page

The JDK

The download for the EWM Client for Eclipse contains the required JDK in the folder jazz/jdk. Unpack the EWM client and use the JDK for your development with the Eclipse Client Libraries and Maven.

The trouble with Maven and the Plain Java Client Libraries.

Unfortunately there is no Maven library for the Plain Java Client Libraries. This is a problem, because there is no real good solution (that I could find) to work with Maven and libraries that do not have a maven repository.

In some projects, I was able to get away with working with Maven and the Plain Java Client Libraries, using an Eclipse User Library with the Plain Java Client Libraries. This works, if at all, only in the Eclipse IDE.

In a recent project this solution was not manageable. I was unable to compile, or I was able to compile, but running the application failed with class not found exceptions. I got it working on my laptop, but we were unable to get it working for a colleague. We lost days.

My usual strategy of using <put your most popular internet search engine here> to find solutions did not really help. Solutions that I found where cryptic, not understandable and/or did not work.

Packaging the Plain Java Client Libraries as local Maven repository.

I finally found this script https://github.com/cokeSchlumpf/mvn-rtc-java-api that allows packaging the plain java client libraries as a maven repository and include that in the application POM file. This allows shipping the Plain Java Client Libraries as Maven repository with the application and its code to be able to run Maven in Eclipse as well as on the command line.

Although the script finally was a life saver, I had some tough learning to get things right. The main issue was that it is a Bash script and my Windows system does not Bash. I tried installing Cygwin64 but realized that I would have to install all kind of stuff to get that working. As I had recently done some other EWM and containerization related work on my NAS, I ended up setting up the required Maven and JDK on my NAS system. I was able to run the script from there 7Zip the result and upload it to my development environment.

In my first attempt, unfortunately, I did not pay enough attention to the format of the dependencies. The dependencies to external libraries has the format <groupId>:<artifactId>:<version>.

# 6.0.2
export DEPENDENCIES="org.apache.james:apache-mime4j:0.6 commons-io:commons-io:1.2 org.apache.httpcomponents:httpclient:4.5 org.apache.httpcomponents:httpclient-cache:4.5 org.apache.httpcomponents:httpclient-win:4.5 org.apache.httpcomponents:httpcore:4.4.1 org.apache.httpcomponents:httpcore-ab:4.4.1 org.apache.httpcomponents:httpcore-nio:4.4.1 org.apache.httpcomponents:httpmime:4.5"

For whatever reason I did not realize that and only provided the <groupId>. This creates an invalid repository. The symptom is the warning message ‘The POM for …. is invalid, transitive dependencies (if any) will not be available’. It took a while to figure out what the reason was. I ended up recreating the repository using the following dependencies values for 7.0.1:

# 7.0.1
export DEPENDENCIES="org.apache.james:apache-mime4j:0.6 commons-io:commons-io:1.2 org.apache.httpcomponents:httpclient:4.5.6 org.apache.httpcomponents:httpclient-cache:4.5.6 org.apache.httpcomponents:httpclient-win:4.5.6 org.apache.httpcomponents:httpcore:4.4.10 org.apache.httpcomponents:httpcore-ab:4.4.10 org.apache.httpcomponents:httpcore-nio:4.4.10 org.apache.httpcomponents:httpmime:4.5.6"

It is totally possible that some of my attempts to fix the above problem made things more miserable. I just realized the severity of the issue when I merged my projects to one and still had the problem.

Please note, if you follow the script above, provide the repository and change the pom of your application and run

mvn clean install

the repository is copied into the local maven repository on your machine. It is stored in the user directory in the folder

.m2/repository/com/ibm/rtc/rtc-java-api

If you build a new version of the repository, make sure to delete the folder above, to make sure your new version is actually installed. Maven does not recognize a difference and will not replace the local files on its own. The reason is that there is no version change visible in the data. This holds true also for the machines of your fellow developers. So when recreating a new Plain Java Client Libraries maven repository with the script, make sure to delete the old local maven repository for the library rtc-java-api in you local .m2 folder as explained above. Then run

mvn clean install

This will recreate the maven library.

I finally succeeded with running

# 7.0.1
export DEPENDENCIES="org.apache.james:apache-mime4j:0.6 commons-io:commons-io:1.2 org.apache.httpcomponents:httpclient:4.5.6 org.apache.httpcomponents:httpclient-cache:4.5.6 org.apache.httpcomponents:httpclient-win:4.5.6 org.apache.httpcomponents:httpcore:4.4.10 org.apache.httpcomponents:httpcore-ab:4.4.10 org.apache.httpcomponents:httpcore-nio:4.4.10 org.apache.httpcomponents:httpmime:4.5.6"

./setup-repo.sh -l ./libs-7.0.1 -r ./repo -d "${DEPENDENCIES}" -v 7.0.1

I followed the readme and added the following to my pom.xml

	<!-- The maven dependency for the EWM Plain Java Client Libraries provided in a local repository -->
		<dependency>
			<groupId>com.ibm.rtc</groupId>
			<artifactId>rtc-java-api</artifactId>
			<version>7.0.1</version>
			<type>pom</type>
		</dependency>

and the repository:

<!-- The maven repository for the EWM Plain Java Client Libraries -->
<repositories>
    <repository>
        <id>project-repo</id>
        <releases>
            <enabled>true</enabled>
            <checksumPolicy>ignore</checksumPolicy>
        </releases>
        <snapshots>
            <enabled>true</enabled>
        </snapshots>
        <url>file://${project.basedir}/repo</url>
    </repository>
</repositories>

The location is based on a project property:

		<project.basedir>${basedir}</project.basedir>

So the files of the repository where copied and located in my Eclipse project in the folder repo in the project root folder.

The repository is bundled in the folder repo

Now it is possible to run Maven from within Eclipse as well as on the shell/command line and my project cleans, installs and liberty:run and the warning mentioned above is gone.

I can only suggest to use the mvn-rtc-java-api – Simple setup RTC Java Client API for Maven project. I would like to thank Victor and Michael for their great contribution. I can only suggest to use it for your purposes.

Whats Next?

I am a bit hesitant to use my personal NAS system as an extended Linux system for development. I will see if I can find some time to understand what the application does in detail and maybe rewrite it in Python. That would make it more operating system independent and allow broader usage.

Summary

As always, I hope that this post helps users out there to achieve their goal and saves some hours of work.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

This site uses Akismet to reduce spam. Learn how your comment data is processed.