Bukama commented on code in PR #598: URL: https://github.com/apache/maven-site/pull/598#discussion_r1917027995
########## content/markdown/whatsnewinmaven4.md: ########## @@ -0,0 +1,496 @@ +<!-- +Licensed to the Apache Software Foundation (ASF) under one +or more contributor license agreements. See the NOTICE file +distributed with this work for additional information +regarding copyright ownership. The ASF licenses this file +to you under the Apache License, Version 2.0 (the +"License"); you may not use this file except in compliance +with the License. You may obtain a copy of the License at + +http://www.apache.org/licenses/LICENSE-2.0 + +Unless required by applicable law or agreed to in writing, +software distributed under the License is distributed on an +"AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY +KIND, either express or implied. See the License for the +specific language governing permissions and limitations +under the License. +--> + +<head> + <title>What's new in Maven 4?</title> + <meta name="author" content="Matthias Bünger" /> +</head> + +# 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 of +its [POM file][2] with Model version 4.0.0. + +The POM file fulfills two elementary needs. +On the one side, the POM holds all the information and configuration, which are only needed to build the artifact. +After the artifact was created, these build information are not relevant anymore. +On the other side, the POM also contains information, e.g. dependencies, which are needed by projects, which want to use +the artifact, e.g. dependencies. +These dependent projects, which "consume" an artifact (and its POM), are called the "consumers" (of an artifact). + +This made the 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. +This results in the situation, that any change in the POM's schema forces each participant of the ecosystem to either +adopt the change or drop support. +So Maven's POM file got cemented, not able to change. + +> "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> + +But Maven should be able to advance. +For this, one important thing that's needed is to separate the information needed for the build from those needed by the +consumers, but without breaking in the ecosystem. +Maven 4 will prepare for this and more. + +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 Review Comment: Will think about another wording tomorrow. Need to go to local JUG now. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: issues-unsubscr...@maven.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org
