I'm trying to figure out how to make my WARs lighter by putting JasperReports, Apache POI and other heavy libs directly to JBoss AS by using JBoss Modules.
Now, Jasper uses many many libraries to generate PDF or XLS files as you can see here. Our templates are pretty old and we are stuck with old jasper version 3.7.1 which of course uses older versions of libraries such as commons which are already present on JBoss AS 7.1.1 modules.
How can I make one "big" module which will contain all jars used by Jasper and keep other parts of application using newer modules?
Putting all jars into separate directories seems so much work without guaranteed success, can we put everything into one module without creating package alike directories?
We started with JBoss modules recently and wrote a small plugin for Maven that generates module folders with module.xmls based on XML descriptors. The plugin is called smartics-jboss-modules-maven-plugin and you'll find additional information about it at the project's blog.
We just started to work with it, but it already makes the process of synchronization between the POM and the module.xml (plus directory structure) for our projects very easy.
The downside of this approach is that you have to learn an additional XML descriptor and have to configure an additional Maven plugin.
If you want to give it a try, the plugin is licensed under Apache License 2.0.
The creation of JBoss modules for external libraries can be automated through maven as explained in another answer here on SO. The author has posted a GitHub project too. This can lessen the pain in managing lots of transitive dependencies.
Related
I'm looking for advice on how to build artifacts that are composed of combinations of multiple modules without repeating a lot of boilerplate for all possibilities:
We have a software that is deployed as a .war into Tomcat and as an .amp into Alfresco running on the same Tomcat instance.
Everything related to Alfresco / .amp does not matter for the scope of the question. For simplicity just assume a single .war artifact in regards to Maven.
We use the open-core model and have a free version that consists of some code that ends up in an .amp and a .war file that contains the Angular-Frontend and several backend libraries.
We have at the moment two plugins in our software - each plugin provides an additional .amp file and adds a .jar / config files to the .war and we have lot's of extensions - each extensions overwrites/extends some Angular-Frontend files and also adds XML-configuration to the .war and/or .amp
Now I'm trying to migrate to Maven from an ancient ant-based build setup that basically just copies the plugins/extensions on deploy time over the base-install.
I need to be able to create configurations like: core + plugin-a + extension-b or core + plugin-a + plugin-b + extension-c - so that I have several .amp artifacts and a single .war artifact for each configuration.
It would be nice if it's also possible to aggregate extensions like core + plugin-a + plugin-b + extension-c + extension-d
At the moment I'm using the maven assembly plugin for the .war and the maven-frontend-plugin for angular and the assembly-plugin just copies the compiled artifacts into the war.
The .war itself is a maven module.
I could go on with this strategy and create modules for every extensions and every plugin but then I will need a module for every possible combination of the extensions and plugins.
To make it worse some extensions/plugins are commercial and live in different repositories - so I can't just add everything to the open-core POM.
I've looked into profiles but I'm not sure if that would solve my problem - as I need something like a central registry for all the submodules?
Somethink like mvn clean package -Pextension-a,extension-b,plugin-a that creates the artifacts would be great.
How to tackle this problem with Maven? Are there projects with these requirements where I can look how it's solved there?
This answer is bit speculative, as I do not know anything about Alfresco.
Have you thought about writing a Maven plugin that downloads an extension/plugin (maybe as zip file from your repository?), unpacks it and applies it to your project?
Then you could call the maven plugin with different lists of extensions/plugins.
In the end I've found Bazel with jvm_rules_external.
The concept of WORKSPACE files that allow dependencies using git/maven/http/etc.pp is perfect for this. Beeing able to also build the Angular frontend using Bazel and create lightweight Docker images as well as the cached incremental builds make it a perfect fit.
However transitioning from Maven to Bazel is not straight forward but after learning the concepts I won't look back!
I am currently starting my adventure with Maven, and I actually don't understand the idea behind using it to automate compilation of my source code. For the time being I am working on small projects with up to 15-20 classes, and 1 main method in the "app" class. Could someone please give me the explanation with examples, when it's necesarry (or recommended) to use build automatation tool to compile the source code and how could I benefit from using it regarding source code compilation?
Thank you very much in advance!
I was looking for different answers and I have a lot of work to do but since I've seen this question, as a Maven fanboy, I couldn't resist anymore and this below is my answer.
First of all, I agree with JF Meier which answered before me, but I think the answer can be improved.
IMO you have to consider Maven not just as a build tool, but as a multi-purpose tool which can help you to do very different things. The best 3, for me are:
Compiler. Obviously. Maven allows you to easily compile giant projects with a lot of submodules, even if some of these modules are interdependent one with each other.
Dependency and repository manager. Maven allows you to automatically download third party software and bind this downlaod to the build. This is immediately understandable if you think to framework or api dependencies from big corps (Apache found., Spark, Spring, Hibernate and so on ...) but it's really powerful in every enterprise context.
Example: you have a Maven project (let's say project A) which manages requests coming from a webservice and provides responses. This Maven project relys on another Maven project (let's say project B) which actually generates webservice jar and uploads it to a company repository. Well, when you have to add a field or a method to the webservice you just have to implements new software in project B, upload it the repo and change the version in Maven poms in both project A and B. Voilà: now EVERY developer of the company just have to "mvn clean install" project A to have the new version.
Sources and code automatic generator. Since Maven 2.x are available a lot of plugins (from Apache found. and others) which allow you to generate code and sources (tipically xml files) starting from little to none implementations.
Example 1: CXF plugin is commonly used to generate java classes from xml or xsd files.
Example 2: JAXWS plugin is commonly used to generate wsdl from SOAP webservice implementations or implementation starting from wsdl file.
Do you feel the power now?
-Andrea
The question is not very specific, but I will try to answer.
Usually, you want your source code to end up in a jar or war, so that you can use it as a library or run it somewhere (e.g. on an application server).
Maven not only compiles the classes you have and creates the final artifact (jar, war), but also handles your dependencies, e.g. the libraries your project depends upon.
I am a total beginner at maven, I have read about it online but I am still confused how it can be used. I have eclipse Oxygen version installed and when I open projects I can see maven project option is already there. I was even able to create a maven project using YouTube tutorial. But now then I saw popular plugin called m2eclipse but I am not able to comprehend why is it actually used; when my application ran without it.
I am learning maven to get started with spring boot but I am finding it really overwhelming where to begin with, and many of the tutorial sites state to download maven (But maven already comes along with eclipse?)
Please explain.
Apache Maven is a build tool - a tool for compiling the source code of a project into a program that you can run (for example a jar file, or a war file that can be deployed on a Java EE application server). Besides automating all the tasks for building a project, it also gives you a standard way to organize your project and to keep track of dependencies (libraries that your project needs).
Why do you need such a tool?
When you write a small program that consists of one, or maybe a few source files, it's easy enough to compile it by hand on the command line, by directly using the Java compiler javac that comes with the JDK.
But when your project becomes more complex, and you have hundreds or even thousands of source files in multiple modules, it becomes really hard to keep track of everything and cumbersome to compile the files using javac. If your program needs libraries, it becomes even more complex, because you have to make sure that all the libraries are on the classpath, and some libraries need other libraries, which also have to be on the classpath.
A tool such as Maven helps you to compile all the source files in the right order and to keep track of all the libraries. Maven can automatically download libraries from the web and add them to your project, and downloading everything and building the whole project can be done with one simple command such as mvn clean package.
Spring Boot is part of the Spring Framework, which is a huge framework with tons of useful functionality for developing projects in Java. A Spring Boot project typically needs dozens of libraries, and it would be very hard to use if you'd have to keep track of all those libraries by hand - so that's why it uses Maven to manage all of this for you.
A Maven project is configured using a file named pom.xml - in that file, you describe your project and you put a list of libraries that your project needs. When you build your project, Maven will read the pom.xml file and figure out automatically what source files need to be compiled, and what libraries need to be downloaded.
m2eclipse comes preinstalled in Eclipse (at least when selecting "Eclipse for Java developers" or "Eclipse for Java EE developer"), thats why you were able to use Maven by default.
Still you probably want a command line Maven, because that's most likely how it will eventually run on the CI server, sometimes Eclipse Maven installation can produce different result than the command line install.
I would like to ask, if there is some maven plugin (or another way) to generate jboss modules hierarchy (with modules.xml files) from maven dependencies (or in list of libraries for such a maven plugin) ?
I have found this plugin :
https://www.smartics.eu/confluence/display/SJBMMP/smartics+JBoss+Modules+Maven+Plugin;jsessionid=3CA5AE2D1DEB5DFB62C1E64692EDCAB6
But documentation / usage pages seem to be offline (or for some reason I cannot open page).
Thank you very much for your help !
I have tried SMARTICS plugin plugin and it created for each maven module special JAR file with ALL dependencies in it.
It is like using maven assembly plugin but all libraries are packed in standalone jar which can be placed into own jboss module. Than in your application : jboss-deployment-structure.xml you reference to this librari (e.g. jar file) and application has all libraries provided.
But splitting dependencies into own directories and generating modules.xml is not possible (confirmed by JBOSS EAP support).
I will create standalone maven project (something like "JBOSS-modules BOM project") which will generate such structure (this structure will be ready for usage on jboss).
I just would like to add an introduction to the mentioned plugin for Maven:
https://www.smartics.eu/confluence/display/BLOG/2013/10/18/Maven+Plugin+to+generate+a+Modules+Directory+for+JBoss+AS+7
The article includes screenshots that help new users to get an idea on how the plugin generates separate modules.
(I would like to comment to your answer, but unfortunately I'm some points from being entitles to do so :( )
I have a GWT webapp split into two Maven projects where one is a dependency to the other. Each time I change something in the dependency and I'm running webapp in hosted mode I have to rebuild the subproject and restart hosted mode for changes to apply. It takes a lot of time so I'd like to ask you if there is any way to make GWT using "live" version of the dependency?
There are 2 cases:
for server-side code, assuming you use the DevMode's embedded server, rebuilding the app and then refreshing the server should be enough
for client-side code, AFAICT, you have to use the source and output directories of the dependency module rather than the JAR containing them (GWT will load the source from the classpath, but apparently it'll only see the modified sources if it comes from a folder rather than a JAR; at least that's what I found in my tests). This goes against The Maven Way™ but the only solution so far is to use a special profile that will import the sources of the dependency project as sources of the project you're running. You can see examples of that in my archetypes.
There's actually a bug opened for the gwt-maven-plugin, MGWT-332, to do that automatically when running a reactor build. I also mused about what's really needed, for the forthcoming official gwt-maven-plugin (rewritten from scratch, independent from the CodeHaus Mojo plugin).
If your dependency does not come from a reactor build, then you're out on your own: you chose to make it totally distinct, so that's how it'll behave: you'll have to release it (even a snapshot) each time you make a change to it, and use the new version in your app (which means re-launching the DevMode).
This can be circumvented by running DevMode on your own, without the help of the gwt-maven-plugin. You're left on your own managing the classpath though (using the Google Plugin for Eclipse, I suppose you could simply edit the launch configuration to add the source folders of your dependency project to the classpath, before the classpath provided by Maven, that would reference the JAR).
Remove the dependent other application jar file from the primary application lib folder under webapp.
Eclipse should then resolve the dependency using the other project in the workspace if you have added it to your primary application classpath.
As GWT build takes ages, we invested some money in a JRebel license. We have two separate Eclipse projects for our back-end and our GWT front-end. JRebel reloads the classes automatically and I never need to restart my local server while writing code. It proved to be a wonderful time saver. Definitely worth the investment.