mvn clean => Cannot invoke "org.apache.maven.repository.internal.ModelCacheFactory.createCache(org.eclipse.aether.RepositorySystemSession)" because "this.modelCacheFactory" is null

[vorburger]

$ /home/vorburger/Downloads/apache-maven-3.9.0-bin/apache-maven-3.9.0/bin/mvn clean
[INFO] Scanning for projects...
[ERROR] Internal error: java.lang.NullPointerException: Cannot invoke "org.apache.maven.repository.internal.ModelCacheFactory.createCache(org.eclipse.aether.RepositorySystemSession)" because "this.modelCacheFactory" is null -> [Help 1]
org.apache.maven.InternalErrorException: Internal error: java.lang.NullPointerException: Cannot invoke "org.apache.maven.repository.internal.ModelCacheFactory.createCache(org.eclipse.aether.RepositorySystemSession)" because "this.modelCacheFactory" is null
    at org.apache.maven.DefaultMaven.execute (DefaultMaven.java:108)
    at org.apache.maven.cli.MavenCli.execute (MavenCli.java:821)
    at org.apache.maven.cli.MavenCli.doMain (MavenCli.java:270)
    at org.apache.maven.cli.MavenCli.main (MavenCli.java:192)
    at jdk.internal.reflect.NativeMethodAccessorImpl.invoke0 (Native Method)
    at jdk.internal.reflect.NativeMethodAccessorImpl.invoke (NativeMethodAccessorImpl.java:77)
    at jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke (DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke (Method.java:568)
    at org.codehaus.plexus.classworlds.launcher.Launcher.launchEnhanced (Launcher.java:282)
    at org.codehaus.plexus.classworlds.launcher.Launcher.launch (Launcher.java:225)
    at org.codehaus.plexus.classworlds.launcher.Launcher.mainWithExitCode (Launcher.java:406)
    at org.codehaus.plexus.classworlds.launcher.Launcher.main (Launcher.java:347)
Caused by: java.lang.NullPointerException: Cannot invoke "org.apache.maven.repository.internal.ModelCacheFactory.createCache(org.eclipse.aether.RepositorySystemSession)" because "this.modelCacheFactory" is null
    at org.apache.maven.project.DefaultProjectBuilder.createModelCache (DefaultProjectBuilder.java:1002)
    at org.apache.maven.project.DefaultProjectBuilder.build (DefaultProjectBuilder.java:362)
    at org.sonatype.maven.polyglot.TeslaProjectBuilder.build (TeslaProjectBuilder.java:43)
    at org.apache.maven.graph.DefaultGraphBuilder.collectProjects (DefaultGraphBuilder.java:349)
    at org.apache.maven.graph.DefaultGraphBuilder.getProjectsForMavenReactor (DefaultGraphBuilder.java:340)
    at org.apache.maven.graph.DefaultGraphBuilder.build (DefaultGraphBuilder.java:76)
    at org.eclipse.tycho.build.TychoGraphBuilder.build (TychoGraphBuilder.java:97)
    at org.apache.maven.DefaultMaven.buildGraph (DefaultMaven.java:453)
    at org.apache.maven.DefaultMaven.doExecute (DefaultMaven.java:196)
    at org.apache.maven.DefaultMaven.doExecute (DefaultMaven.java:172)
    at org.apache.maven.DefaultMaven.execute (DefaultMaven.java:100)
    at org.apache.maven.cli.MavenCli.execute (MavenCli.java:821)
    at org.apache.maven.cli.MavenCli.doMain (MavenCli.java:270)
    at org.apache.maven.cli.MavenCli.main (MavenCli.java:192)
    at jdk.internal.reflect.NativeMethodAccessorImpl.invoke0 (Native Method)
    at jdk.internal.reflect.NativeMethodAccessorImpl.invoke (NativeMethodAccessorImpl.java:77)
    at jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke (DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke (Method.java:568)
    at org.codehaus.plexus.classworlds.launcher.Launcher.launchEnhanced (Launcher.java:282)
    at org.codehaus.plexus.classworlds.launcher.Launcher.launch (Launcher.java:225)
    at org.codehaus.plexus.classworlds.launcher.Launcher.mainWithExitCode (Launcher.java:406)
    at org.codehaus.plexus.classworlds.launcher.Launcher.main (Launcher.java:347)
[ERROR]
[ERROR] To see the full stack trace of the errors, re-run Maven with the -e switch.
[ERROR] Re-run Maven using the -X switch to enable full debug logging.
[ERROR]
[ERROR] For more information about the errors and possible solutions, please read the following articles:
[ERROR] [Help 1] http://cwiki.apache.org/confluence/display/MAVEN/InternalErrorException

[vorburger]

According to eclipse-tycho/tycho#2063, this is because (quote) "Tycho currently do not support maven 3.9", and will be fixed with (and after a release of) eclipse-tycho/tycho#2058.

Indeed, when I use Maven 3.8.7 instead of 3.9.0 then I'm not hitting this problem anymore (but #447 instead).

All the more reason to contrib #445...