Investigate support for Maven 4.0

[mhalbritter]

It's currently in RC-1: https://maven.apache.org/docs/4.0.0-rc-1/release-notes.html

[mhalbritter]

Creating a plain project on start.spring.io and running it with Maven 4 gives you a bunch of warnings:

[WARNING] 
[WARNING] Some problems were encountered while building the effective model for 'com.example:maven4:jar:0.0.1-SNAPSHOT'
[WARNING] Ignored POM import for: io.micrometer:micrometer-commons:jar:1.14.0@compile as already imported io.micrometer:micrometer-commons:jar:1.14.1@compile. Add the conflicting managed dependency directly to the dependencyManagement section of the POM.
[WARNING] Ignored POM import for: io.micrometer:micrometer-core:jar:1.14.0@compile as already imported io.micrometer:micrometer-core:jar:1.14.1@compile. Add the conflicting managed dependency directly to the dependencyManagement section of the POM.
[WARNING] Ignored POM import for: io.micrometer:micrometer-jakarta9:jar:1.14.0@compile as already imported io.micrometer:micrometer-jakarta9:jar:1.14.1@compile. Add the conflicting managed dependency directly to the dependencyManagement section of the POM.
[WARNING] Ignored POM import for: io.micrometer:micrometer-java11:jar:1.14.0@compile as already imported io.micrometer:micrometer-java11:jar:1.14.1@compile. Add the conflicting managed dependency directly to the dependencyManagement section of the POM.
[WARNING] Ignored POM import for: io.micrometer:micrometer-java21:jar:1.14.0@compile as already imported io.micrometer:micrometer-java21:jar:1.14.1@compile. Add the conflicting managed dependency directly to the dependencyManagement section of the POM.
[WARNING] Ignored POM import for: io.micrometer:micrometer-jetty11:jar:1.14.0@compile as already imported io.micrometer:micrometer-jetty11:jar:1.14.1@compile. Add the conflicting managed dependency directly to the dependencyManagement section of the POM.
[WARNING] Ignored POM import for: io.micrometer:micrometer-jetty12:jar:1.14.0@compile as already imported io.micrometer:micrometer-jetty12:jar:1.14.1@compile. Add the conflicting managed dependency directly to the dependencyManagement section of the POM.
[WARNING] Ignored POM import for: io.micrometer:micrometer-observation:jar:1.14.0@compile as already imported io.micrometer:micrometer-observation:jar:1.14.1@compile. Add the conflicting managed dependency directly to the dependencyManagement section of the POM.
[WARNING] Ignored POM import for: io.micrometer:micrometer-observation-test:jar:1.14.0@compile as already imported io.micrometer:micrometer-observation-test:jar:1.14.1@compile. Add the conflicting managed dependency directly to the dependencyManagement section of the POM.
[WARNING] Ignored POM import for: io.micrometer:micrometer-registry-appoptics:jar:1.14.0@compile as already imported io.micrometer:micrometer-registry-appoptics:jar:1.14.1@compile. Add the conflicting managed dependency directly to the dependencyManagement section of the POM.
[WARNING] Ignored POM import for: io.micrometer:micrometer-registry-atlas:jar:1.14.0@compile as already imported io.micrometer:micrometer-registry-atlas:jar:1.14.1@compile. Add the conflicting managed dependency directly to the dependencyManagement section of the POM.
[WARNING] Ignored POM import for: io.micrometer:micrometer-registry-azure-monitor:jar:1.14.0@compile as already imported io.micrometer:micrometer-registry-azure-monitor:jar:1.14.1@compile. Add the conflicting managed dependency directly to the dependencyManagement section of the POM.
[WARNING] Ignored POM import for: io.micrometer:micrometer-registry-cloudwatch2:jar:1.14.0@compile as already imported io.micrometer:micrometer-registry-cloudwatch2:jar:1.14.1@compile. Add the conflicting managed dependency directly to the dependencyManagement section of the POM.
[WARNING] Ignored POM import for: io.micrometer:micrometer-registry-datadog:jar:1.14.0@compile as already imported io.micrometer:micrometer-registry-datadog:jar:1.14.1@compile. Add the conflicting managed dependency directly to the dependencyManagement section of the POM.
[WARNING] Ignored POM import for: io.micrometer:micrometer-registry-dynatrace:jar:1.14.0@compile as already imported io.micrometer:micrometer-registry-dynatrace:jar:1.14.1@compile. Add the conflicting managed dependency directly to the dependencyManagement section of the POM.
[WARNING] Ignored POM import for: io.micrometer:micrometer-registry-elastic:jar:1.14.0@compile as already imported io.micrometer:micrometer-registry-elastic:jar:1.14.1@compile. Add the conflicting managed dependency directly to the dependencyManagement section of the POM.
[WARNING] Ignored POM import for: io.micrometer:micrometer-registry-ganglia:jar:1.14.0@compile as already imported io.micrometer:micrometer-registry-ganglia:jar:1.14.1@compile. Add the conflicting managed dependency directly to the dependencyManagement section of the POM.
[WARNING] Ignored POM import for: io.micrometer:micrometer-registry-graphite:jar:1.14.0@compile as already imported io.micrometer:micrometer-registry-graphite:jar:1.14.1@compile. Add the conflicting managed dependency directly to the dependencyManagement section of the POM.
[WARNING] Ignored POM import for: io.micrometer:micrometer-registry-health:jar:1.14.0@compile as already imported io.micrometer:micrometer-registry-health:jar:1.14.1@compile. Add the conflicting managed dependency directly to the dependencyManagement section of the POM.
[WARNING] Ignored POM import for: io.micrometer:micrometer-registry-humio:jar:1.14.0@compile as already imported io.micrometer:micrometer-registry-humio:jar:1.14.1@compile. Add the conflicting managed dependency directly to the dependencyManagement section of the POM.
[WARNING] Ignored POM import for: io.micrometer:micrometer-registry-influx:jar:1.14.0@compile as already imported io.micrometer:micrometer-registry-influx:jar:1.14.1@compile. Add the conflicting managed dependency directly to the dependencyManagement section of the POM.
[WARNING] Ignored POM import for: io.micrometer:micrometer-registry-jmx:jar:1.14.0@compile as already imported io.micrometer:micrometer-registry-jmx:jar:1.14.1@compile. Add the conflicting managed dependency directly to the dependencyManagement section of the POM.
[WARNING] Ignored POM import for: io.micrometer:micrometer-registry-kairos:jar:1.14.0@compile as already imported io.micrometer:micrometer-registry-kairos:jar:1.14.1@compile. Add the conflicting managed dependency directly to the dependencyManagement section of the POM.
[WARNING] Ignored POM import for: io.micrometer:micrometer-registry-new-relic:jar:1.14.0@compile as already imported io.micrometer:micrometer-registry-new-relic:jar:1.14.1@compile. Add the conflicting managed dependency directly to the dependencyManagement section of the POM.
[WARNING] Ignored POM import for: io.micrometer:micrometer-registry-opentsdb:jar:1.14.0@compile as already imported io.micrometer:micrometer-registry-opentsdb:jar:1.14.1@compile. Add the conflicting managed dependency directly to the dependencyManagement section of the POM.
[WARNING] Ignored POM import for: io.micrometer:micrometer-registry-otlp:jar:1.14.0@compile as already imported io.micrometer:micrometer-registry-otlp:jar:1.14.1@compile. Add the conflicting managed dependency directly to the dependencyManagement section of the POM.
[WARNING] Ignored POM import for: io.micrometer:micrometer-registry-prometheus:jar:1.14.0@compile as already imported io.micrometer:micrometer-registry-prometheus:jar:1.14.1@compile. Add the conflicting managed dependency directly to the dependencyManagement section of the POM.
[WARNING] Ignored POM import for: io.micrometer:micrometer-registry-prometheus-simpleclient:jar:1.14.0@compile as already imported io.micrometer:micrometer-registry-prometheus-simpleclient:jar:1.14.1@compile. Add the conflicting managed dependency directly to the dependencyManagement section of the POM.
[WARNING] Ignored POM import for: io.micrometer:micrometer-registry-signalfx:jar:1.14.0@compile as already imported io.micrometer:micrometer-registry-signalfx:jar:1.14.1@compile. Add the conflicting managed dependency directly to the dependencyManagement section of the POM.
[WARNING] Ignored POM import for: io.micrometer:micrometer-registry-statsd:jar:1.14.0@compile as already imported io.micrometer:micrometer-registry-statsd:jar:1.14.1@compile. Add the conflicting managed dependency directly to the dependencyManagement section of the POM.
[WARNING] Ignored POM import for: io.micrometer:micrometer-registry-wavefront:jar:1.14.0@compile as already imported io.micrometer:micrometer-registry-wavefront:jar:1.14.1@compile. Add the conflicting managed dependency directly to the dependencyManagement section of the POM.
[WARNING] Ignored POM import for: io.micrometer:micrometer-test:jar:1.14.0@compile as already imported io.micrometer:micrometer-test:jar:1.14.1@compile. Add the conflicting managed dependency directly to the dependencyManagement section of the POM.
[WARNING] Ignored POM import for: org.apache.maven.plugin-tools:maven-plugin-annotations:jar:3.7.0@compile as already imported org.apache.maven.plugin-tools:maven-plugin-annotations:jar:3.13.1@compile. Add the conflicting managed dependency directly to the dependencyManagement section of the POM.
[WARNING] 
[WARNING] It is highly recommended to fix these problems because they threaten the stability of your build.
[WARNING] 
[WARNING] For this reason, future Maven versions might no longer support building such malformed projects.
[WARNING]

[wilkinsona]

I've seen this one before:

Ignored POM import for: org.apache.maven.plugin-tools:maven-plugin-annotations:jar:3.7.0@compile as already imported org.apache.maven.plugin-tools:maven-plugin-annotations:jar:3.13.1@compile. Add the conflicting managed dependency directly to the dependencyManagement section of the POM.

It has been fixed in apache/maven-apache-parent#265 but it'll take a while for all Apache-related projects to move to the new parent.