We Keep Coding

How to make the Maven child project to have different version than the parent?

I am very new to Maven, and I am creating a Maven parent and child project. I want the child project to have a different version than the parent, but if I change the version, then I am getting the error Cannot resolve for some of the dependencies.
How can I have a have a parent version different than the child version?
Following are the current properties I have, which are working pretty fine:
<modelVersion>4.0.0</modelVersion>
<parent>
<groupId>io.parent-test</groupId>
<artifactId>io.parent-test</artifactId>
<version>0.9.1-SNAPSHOT</version>
<relativePath></relativePath>
</parent>
<artifactId>test-project-converter</artifactId>
<name>test-project</name>
<description>Test Project</description>
If I change the properties to include the different version for child then I get the error:
<modelVersion>4.0.0</modelVersion>
<parent>
<groupId>io.parent-test</groupId>
<artifactId>io.parent-test</artifactId>
<version>0.9.1-SNAPSHOT</version>
<relativePath></relativePath>
</parent>
<version>0.9.2-SNAPSHOT</version>
<artifactId>test-project-converter</artifactId>
<name>test-project</name>
<description>Test Project</description>
I have the following dependencies based on the version that is throwing the error:
<dependency>
<groupId>io.parent-dep</groupId>
<artifactId>parent-dev</artifactId>
<version>${project.version}</version>
</dependency>
I tried to look into some of the responses online and made modifications to my parent project to include the properties:
<properties>
<revision>0.9.2-SNAPSHOT</revision>
</properties>
and accordingly, change the child project to include the version <version>${revision}</version> but it's not working as expected.
Can someone please let me know how can I create a different snapshot version for my child project while keeping the parent project same?

I think because you are building wrong order of child and parent project. When you change the version of child project, you should first re-build child project with new version -> new jar file name (with old parent jar file if in the child project have parent dependency) then update the version of child dependency in the pom file of parent project and re-build parent project, then re-build child project again with the new parent jar file (the same version but include different child jar file).

I was able to fix it by providing the parent version ${project.parent.version} to the dependencies coming from the parent.
I tried this, and everything worked fine.
<modelVersion>4.0.0</modelVersion>
<parent>
<groupId>io.parent-test</groupId>
<artifactId>io.parent-test</artifactId>
<version>0.9.1-SNAPSHOT</version>
<relativePath></relativePath>
</parent>
<version>0.9.2-SNAPSHOT</version>
<artifactId>test-project-converter</artifactId>
<name>test-project</name>
<description>Test Project</description>
<dependencies>
<dependency>
<groupId>io.parent-dep</groupId>
<artifactId>parent-dev</artifactId>
<version>${project.parent.version}</version>
</dependency>
</dependencies>

Maven nested dependency is not accessible

I have a maven project and in the parent POM and I have declared some dependencies inside this parent POM. This POM is used within the child POM as shown in the code snippet. When compiling the Child project, IntelliJ complains that it cannot find an interface used within the parent project.This interface is declared within the dependency "anotherApp" in the parent POM.
My understanding about Maven dependencies is that, since I have declared the dependency in Parent POM, it should get inherited in the child POM as well and child should be able to access these dependencies and their classes / interfaces without an issue.
I tried adding the dependency inside dependencyManagement tag in parent POM. But cannot achieve what I expect to get. I also looked into the dependency trees of both parent and child projects. In parent, dependency tree shows anotherApp as its dependency, but in child, only parent is shown as a dependency, anotherApp is not shown as a dependency came through parent.
This is how my parent POM looks like
<project>
<modelVersion>4.0.0</modelVersion>
<parent>
<groupId>it.app</groupId>
<artifactId>commonParent</artifactId>
<version>1.0-SNAPSHOT</version>
<relativePath>../CommonParent/pom.xml</relativePath>
</parent>
<groupId>com.app</groupId>
<artifactId>parent</artifactId>
<version>0.1-SNAPSHOT</version>
<packaging>jar</packaging>
<dependencies>
<dependency>
<groupId>com.myapp</groupId>
<artifactId>anotherApp</artifactId>
<version>2.0-SNAPSHOT</version>
</dependency>
</dependencies>
</project>
This is how my child POM looks like
<project>
<modelVersion>4.0.0</modelVersion>
<parent>
<groupId>it.app</groupId>
<artifactId>commonParent</artifactId>
<version>1.0-SNAPSHOT</version>
<relativePath>../CommonParent/pom.xml</relativePath>
</parent>
<groupId>com.app</groupId>
<artifactId>child</artifactId>
<version>0.1-SNAPSHOT</version>
<packaging>jar</packaging>
<dependencies>
<dependency>
<groupId>com.app</groupId>
<artifactId>parent</artifactId>
</dependency>
</dependencies>
</project>
There is an interface Foo declared inside "anotherApp". This interface is accessible by the parent project. But child project cannot access this interface. IntelliJ complains that it cannot access this interface.

Two things that need to be corrected:
The parent POM should have <packaging>pom</packaging>.
The child project should not use the parent POM as dependency, but add it in the <parent> tag.

How to update child pom version using maven and jenkins

I have created a jenkins job where I am passing ReleaseNumber as a parameter, I want this ReleaseNumber to be updated in every pom.xml file (root and child pom), since I am uploading these wars in nexus repository, same version number wont be accepted by nexus.
I want to update child pom version and parent pom version as well.
I am using maven 3.5
I am using this command which I think its not working
mvn org.codehaus.mojo:versions-maven-plugin:2.5:set -DnewVersion-${ReleaseNumber}
This is my parent pom looks like
<modelVersion>4.0.0</modelVersion>
<groupId>com.test.test</groupId>
<artifactId>Wars</artifactId>
<version>1.0.0</version>
<packaging>pom</packaging>
and this is my child pom looks like
<parent>
<groupId>com.test.test</groupId>
<artifactId>TestWar</artifactId>
<version>1.0.0</version>
</parent>
<modelVersion>4.0.0</modelVersion>
<groupId>com.test.test.testwar</groupId>
<artifactId>TestWar</artifactId>
<version>1.0.0</version>
<packaging>war</packaging>
<name>testWar</name>
Thanks In Advance

Is there a variable ${ReleaseNumber} defined in pom? Or you just copy/pasted it?
You have typo, not - but =
-DnewVersion=${ReleaseNumber}

How to make existing maven parent project, child of newly created maven project

I have existing maven Project(named as projectB) that is parent of other Projects(projectC and projectD), and I want to make projectB as child of newly created maven Project(named as projectA). This is Directory structure:
projectA
-> pom.xml
projectB
-> pom.xml
projectC
-> pom.xml
projectD
-> pom.xml
This is how my pom.xml of projectA looks:
<modules>
<module>projectB</module>
</modules>
And this is my pom.xml of projectB Looks:
<parent>
<groupId>(groupId of projectA)</groupId>
<artifactId>projectA</artifactId>
<version>0.0.1-SNAPSHOT</version>
</parent>
<modules>
<module>../projectC</module>
<module>../projectD</module>
</modules>
But when I perform make clean on projectA it gives me error:
Child module C:\Users\projectB of C:\Users\projectA\pom.xml does not exist
I have searched existing solutions, but none has helped me in solving the problem.

Since your all projects are all in the same level, you should have:
In Project A:
<modules>
<module>../projectB</module>
</modules>
And in Project B:
<parent>
...
<relativePath>../projectA/pom.xml</relativePath>
</parent>

Below Configuration in pom.xml of Project B is incorrect
<parent>
<groupId>(groupId of projectB)</groupId>
<artifactId>projectB</artifactId>
<version>0.0.1-SNAPSHOT</version>
</parent>
In parent section, you have to specify Project A not B. Something like below should help
<parent>
<groupId>(groupId of projectA)</groupId>
<artifactId>projectA</artifactId>
<version>(Project A version)</version>
</parent>

How to specify maven properties in a aggregator POM?

I have a project structure like below.In aggregator POM project1 and project 2 are defined as modules.Now if i want to add a maven property that can be accessed in all the projects how can i do it?.
What is the best project structure in this case.?
If i define property like <temp.dir>data</temp.dir> in the aggregator POM then it is not available in project1 pom.xml and project2 POM.xml.I have to duplicate the same property in both the POM's.
project
- project1
- - pom.xml ---- has parent POM as project A
- project2
- - pom.xml --- has parent POM as project B
- pom.xml (Aggregator POM)
UPDATE:To clarify more project1 pom and project 2 has different parent POM's.So aggregator POM cannot be set as parent.

You need to set the aggregator pom as the parent of project1 and project2.
eg. in project1 and project2 poms add:
<parent>
<groupId>com.agr</groupId>
<artifactId>project-aggregator</artifactId>
<version>1.0.0</version>
</parent>
EDIT:
I understand that project1 and project2 have different parent poms.
The only solution i know about to achieve what You want is to store the properties in parent pom.
I can think only of one solution, to make an inheritance chain:
Project2Parent:
<parent>
<groupId>com.test</groupId>
<artifactId>Project1Parent</artifactId>
<version>0.0.1</version>
</parent>
<artifactId>Project2Parent</artifactId>
<version>0.0.1</version>
Aggregator:
<parent>
<groupId>com.test</groupId>
<artifactId>Project2Parent</artifactId>
<version>0.0.1</version>
</parent>
<artifactId>Aggregator</artifactId>
<version>0.0.1</version>
Project1
<parent>
<groupId>com.test</groupId>
<artifactId>Aggregator</artifactId>
<version>0.0.1</version>
</parent>
<artifactId>project1</artifactId>
<version>0.0.1</version>
Project2
<parent>
<groupId>com.test</groupId>
<artifactId>Aggregator</artifactId>
<version>0.0.1</version>
</parent>
<artifactId>project2</artifactId>
<version>0.0.1</version>

Here is aggregator's pom:
<groupId>y</groupId>
<artifactId>y</artifactId>
<version>0.0.1</version>
<packaging>pom</packaging>
<modules>
<module>y1</module>
<module>y2</module>
</modules>
<properties>
<x>1</x>
</properties>
This is y1 effective pom (generated by Eclipse):
<parent>
<groupId>y</groupId>
<artifactId>y</artifactId>
<version>0.0.1</version>
</parent>
<groupId>y1</groupId>
<artifactId>y1</artifactId>
<version>0.0.1</version>
<properties>
<x>1</x>
</properties>
As you can see property x declared in parent is inherited by child.