[MNG-7318] NullPointerException during mvn install when property is called "project.version"

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 3.6.3
• Fix Version/s: 3.8.1
• Component/s: Command Line, Inheritance and Interpolation

Environment

Apache Maven 3.6.3
Maven home: /usr/share/maven
Java version: 1.8.0_221, vendor: Oracle Corporation, runtime: /usr/lib/jvm/jdk1.8.0_221/jre
Default locale: en_US, platform encoding: UTF-8
OS name: "linux", version: "5.11.0-38-generic", arch: "amd64", family: "unix"

• Assignee: Sylwester Lachiewicz
• Reporter: Daniel Langerenken
• Created: 01/Nov/21 19:41
• Updated: 07/Jan/22 19:27
• Resolved: 07/Jan/22 19:27

Description

Use the following (simplified) pom.xml and run mvn install:

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://maven.apache.org/POM/4.0.0" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
  <modelVersion>4.0.0</modelVersion>
  <groupId>org.example</groupId>
  <artifactId>foo</artifactId>
  <version>${revision}</version>
  <properties>
    <project.version>1.0</project.version>
    <revision>${project.version}</revision>
  </properties>
</project>

It will throw the following exception:

 [ERROR] Internal error: java.lang.NullPointerException -> [Help 1]
org.apache.maven.InternalErrorException: Internal error: java.lang.NullPointerException
    at org.apache.maven.DefaultMaven.execute (DefaultMaven.java:120)
    at org.apache.maven.cli.MavenCli.execute (MavenCli.java:957)
    at org.apache.maven.cli.MavenCli.doMain (MavenCli.java:289)
    at org.apache.maven.cli.MavenCli.main (MavenCli.java:193)
    at sun.reflect.NativeMethodAccessorImpl.invoke0 (Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke (NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke (DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke (Method.java:498)
    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
    at java.util.Hashtable$Entry.setValue (Hashtable.java:1286)
    at org.apache.maven.model.interpolation.StringVisitorModelInterpolator$ModelVisitor.visit (StringVisitorModelInterpolator.java:1429)
    at org.apache.maven.model.interpolation.StringVisitorModelInterpolator$ModelVisitor.visit (StringVisitorModelInterpolator.java:1027)
    at org.apache.maven.model.interpolation.StringVisitorModelInterpolator$ModelVisitor.visit (StringVisitorModelInterpolator.java:170)
    at org.apache.maven.model.interpolation.StringVisitorModelInterpolator.interpolateModel (StringVisitorModelInterpolator.java:107)
    at org.apache.maven.model.building.DefaultModelBuilder.interpolateModel (DefaultModelBuilder.java:789)
    at org.apache.maven.model.building.DefaultModelBuilder.build (DefaultModelBuilder.java:393)
    at org.apache.maven.project.DefaultProjectBuilder.build (DefaultProjectBuilder.java:448)
    at org.apache.maven.project.DefaultProjectBuilder.build (DefaultProjectBuilder.java:414)
    at org.apache.maven.project.DefaultProjectBuilder.build (DefaultProjectBuilder.java:377)
    at org.apache.maven.graph.DefaultGraphBuilder.collectProjects (DefaultGraphBuilder.java:414)
    at org.apache.maven.graph.DefaultGraphBuilder.getProjectsForMavenReactor (DefaultGraphBuilder.java:405)
    at org.apache.maven.graph.DefaultGraphBuilder.build (DefaultGraphBuilder.java:82)
    at org.apache.maven.DefaultMaven.buildGraph (DefaultMaven.java:507)
    at org.apache.maven.DefaultMaven.doExecute (DefaultMaven.java:219)
    at org.apache.maven.DefaultMaven.doExecute (DefaultMaven.java:192)
    at org.apache.maven.DefaultMaven.execute (DefaultMaven.java:105)
    at org.apache.maven.cli.MavenCli.execute (MavenCli.java:957)
    at org.apache.maven.cli.MavenCli.doMain (MavenCli.java:289)
    at org.apache.maven.cli.MavenCli.main (MavenCli.java:193)

This is only happening when I name the property `project.version` indicating that this might be an illegal name. I can switch it to `project.ver` and it works fine.

This should not throw a NullPointerException but instead either work or throw an appropriate exception.

Issue Links

• is fixed by: MNG-6819 NullPointerException for DefaultArtifactDescriptorReader.loadPom