Why Maven throws error like `must be "pom" but is "jar"`?

Question

I need to fix below maven error.

When I run:

mvn clean install

I get :

[ERROR] The build could not read 1 project -> [Help 1]
org.apache.maven.project.ProjectBuildingException: Some problems were encountered while processing the POMs:
[ERROR] Invalid packaging for parent POM org.springframework.boot:spring-boot-starter-parent:2.0.5.RELEASE, must be "pom" but is "jar" @ org.springframework.boot:spring-boot-starter-parent:2.0.5.RELEASE
[ERROR] 'packaging' with value 'jar' is invalid. Aggregator projects require 'pom' as packaging. @ line 3, column 102

This is my package hierarchy:

.
├── pom.xml
|
└── application
    └── pom.xml

Below is my pom in root:

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <groupId>com.tim.project</groupId>
    <artifactId>myservice</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>${project.artifactId}-${project.version}</name>
    <description>My Service</description>
    <packaging>pom</packaging>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    </properties>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.0.5.RELEASE</version>
        <relativePath/>
    </parent>

    <modules>
        <module>application</module>
    </modules>

</project>

Below is my pom in application folder:

<?xml version="1.0" encoding="UTF-8"?>
<project xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"
         xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">

    <modelVersion>4.0.0</modelVersion>
    <groupId>com.tom.project</groupId>
    <artifactId>myservice-application</artifactId>
    <version>0.0.2</version>
    <packaging>jar</packaging>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <java.version>1.8</java.version>
    </properties>

    <repositories>
        <repository>
          ...
        </repository>
    </repositories>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-sleuth</artifactId>
                <version>2.0.0.RC1</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>

    <dependencies>
      <dependency>
          <groupId>org.springframework.boot</groupId>
          <artifactId>spring-boot-starter-web</artifactId>
          <scope>compile</scope>
      </dependency>
      ....
      ....

    </dependencies>

</project>

`mvn -f application_pom_file.xml clean install` would it help? — grog, Dec 11 '19 at 14:00

score 1 · Accepted Answer · answered Dec 11 '19 at 14:54

1

pom.xml in application folder is missing:

<parent>
    <groupId>com.tim.project</groupId>
    <artifactId>myservice</artifactId>
    <version>0.0.1-SNAPSHOT</version>
</parent>

answered Dec 11 '19 at 14:54

jirka.pinkas

918
6
21

Raffaele · Answer 2 · 2019-12-11T14:19:06.610

0

<parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.0.5.RELEASE</version>
        <relativePath/>
    </parent>

try removing <relativePath/> and replace it with <type>pom</type>

EDIT

I have something really similar: the root pom

<groupId>org.company</groupId>
    <artifactId>my-parent</artifactId>
    <version>1.1</version>
    <packaging>pom</packaging>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.1.8.RELEASE</version>
    </parent>

then the applications:

<artifactId>my-spring-app</artifactId>
    <packaging>jar</packaging>

    <parent>
        <groupId>org.company</groupId>
        <artifactId>my-parent</artifactId>
        <version>1.1</version><!-- version can be different of course-->
    </parent>

edited Dec 11 '19 at 14:19

answered Dec 11 '19 at 14:04

Raffaele

461
1
7
20

1

Element type is not allowed here. – Tim Tuckle Dec 11 '19 at 14:08
just remove relativePath then – Raffaele Dec 11 '19 at 14:09
Anyway why u don't specify the parent in your application pom? I mean there is no reference to the upper level pom (the one in the root) – Raffaele Dec 11 '19 at 14:12
Does this help?: https://stackoverflow.com/questions/18733729/packaging-jar-is-invalid-aggregator-project-need-pom-as-packaging – benji2505 Dec 11 '19 at 14:36

Why Maven throws error like `must be "pom" but is "jar"`?

2 Answers2