[
https://issues.apache.org/jira/browse/MNGSITE-550?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17908570#comment-17908570
]
ASF GitHub Bot commented on MNGSITE-550:
----------------------------------------
Bukama commented on code in PR #598:
URL: https://github.com/apache/maven-site/pull/598#discussion_r1898872695
##########
content/markdown/whatsnewinmaven4.md:
##########
@@ -0,0 +1,466 @@
+# What's New in Maven 4?
+
+Maven is over 20 years old, and is one of the most used build tools in the
Java world.
+Throughout the years, one important rule has been maintaining the highest
backward compatibility possible, especially
+with its [POM-schema with Model version 4.0.0][2], used not only for the build
itself but also by consumers.
+This made Maven more than a tool; it became a whole ecosystem with many
dependencies on the POM, especially the Maven
+Central repository, other build tools, and IDEs.
+
+> "With the Maven build schema preserved in amber, we can’t evolve much: we’ll
stay forever with Maven 3 minor releases,
+> unable to implement improvements that we imagine will require seriously
updating the POM schema…"
+> — <cite>[Hervé Boutemy (in Javaadvent 2021)][1]</cite>
+
+Maven 4 will prepare for changes which are impossible nowadays, like a
completely new build schema.
+
+Another pain point of Maven 3 is a codebase with a lot of deprecated,
convoluted, and duplicate code
+which costs the developers who maintain Maven a lot of time.
+This means that the Maven codebase contains not only old Java code but also
old dependencies and poor API design of its
+own APIs, especially for Maven plugins.
+Therefore, Maven 4 will also be a maintenance release.
+
+This article presents and explains major changes brought by Maven 4, grouped
into several topics.
+
+## POM Changes
+
+### Build-POM and Consumer-POM
+
+As written in the introduction, Model version 4.0.0 is used not only by the
build but also by consumers of the
+artifact.
+However, several parts of the POM are only necessary for the build while
others, like the dependencies, are also
+needed by the consumers.
+Maven 4 will therefore differentiate between a "Build-POM" and a
"Consumer-POM".
+As the names suggest, the "Build-POM" will contain all information needed to
build the artifact, e.g., applied plugins
+and their configuration, while the "Consumer-POM", which is created during the
Maven build, only contains what is
+necessary.
+This POM will only keep what is really needed to use the artifact, e.g.,
dependency information.
+
+**Note**: See below for a comparison of the content of both POMs.
+
+### Model version 4.1.0
+
+With two types of POM, Maven 4 can make additions to the Build-POM as it is
only be used by Maven.
+Therefore, with Maven 4, a new Model version 4.1.0 is introduced.
+This version adds some new elements and attributes, while others are marked as
deprecated.
+To not break the ecosystem, this version is only available for the Build-POM,
while the Consumer-POM will still use
+version 4.0.0.
+Maven generates the Consumer-POM during the build from the build POM.
+
+**Note**: Maven 4 will continue to build your model version 4.0.0 project.
+There is no need to update your POMs to 4.1.0 as long as you don't want to
make use of the new features.
+
+### Modules are now subprojects
+
+From the early days of Maven 1 until today, all build information is stored in
the POM, short for "Project Object
+Model".
+Together with build folders and other files, the wording "Maven project" is
used.
+However, for projects containing multiple parts, e.g., an API and a client,
each of those parts was called a "module"
+and listed in the `<modules>` section of the POM, leading to the terms
"multi-module project".
+This wording introduced some inconsistency, especially as projects without any
`<modules>` section are often called "
+single-module".
+Since the introduction of the [Java Platform Module System][3] in Java 9, the
term "module" has raised additional
+confusion.
+
+Maven 4 gets rid of this by naming "modules" as what they are - subprojects.
+Model version 4.1.0 contains a new `<subprojects>` element analogous to the
now deprecated, but still usable,
+`<modules>` element.
+
+**Note**: Use the terms `multi-project setup` and `single-project setup` to
differentiate between a Maven project with
+or without subprojects.
+
+### New packaging type: bom
+
+Maven 4 introduces a dedicated packaging type to provide a [Bill of Materials
BOM][4] called "bom" to differentiate more
+precisely between "parent POMs" and dependency-managing BOMs.
+While the new type is only available with Model Version 4.1.0, the final
outcome is a full Maven 3 compatible (model
Review Comment:
Rephrased
> Information about "What's new in Maven 4?"
> ------------------------------------------
>
> Key: MNGSITE-550
> URL: https://issues.apache.org/jira/browse/MNGSITE-550
> Project: Maven Project Web Site
> Issue Type: Improvement
> Reporter: Matthias Bünger
> Priority: Major
>
> A comprehensive article/list of the important changes in Maven 4 is needed.
> ----
>
> Issue based on the slack message / thread, started by [~cstamas]
> {quote}
> More and more times we get questions like "and what is new in Maven4?". We
> have no document that distills the relevant changes. Could someone try to
> collect that in cwiki or somewhere?
> {quote}
--
This message was sent by Atlassian Jira
(v8.20.10#820010)
