Thread: Mvn (Maven) not recognized as command

Sorry, I don’t know what the appropriate forum for this question is.

I am following a course Maven Fundamentals on Pluralsight.

I installed Spring Tools Suite 4 and Maven.
Maven I installed on the G drive and I assumed that is why it didn’t work.

In the command prompt instructing
mvn –version
yields
'mvn' is not recognized as an internal or external command, operable program or batch file.

However, I tried putting it in a few places on the C drive, but that didn’t help.

There is however a difference that puzzles me. I am talking about the setting found at (translated from Dutch)
System Variables → Environment Variables → in table System Variables select ‘Path’ → Edit…

The first time I did that I got a table with lines and I could add the line %MAVEN_HOME%bin
Now eacht time I go there the table is compacted in a single line, like this :
%JAVA_HOME%\bin;%MAVEN_HOME%\bin%;TRICENTIS_SEARCH %;%SystemRoot%\system32;%SystemRoot%;%SystemRoot%\ System32\Wbem;%SYSTEMROOT%\System32\WindowsPowerSh ell\v1.0\;%SYSTEMROOT%\System32\OpenSSH\;C:\Progra m Files\Java\jdk-18.0.2.1\bin;C:\Program Files (x86)\dotnet\;C:\Program Files\dotnet\;

How can I explain to the command prompt where to find the mvn command ?

Thanks for your response.

Now Maven is in
C:\Dev\apache-maven-3.8.6

It does not contain an .exe file, so I don’t know how to run it.

The System variable MAVEN_HOME is
C:\Program Files\Dev\apache-maven-3.8.6

That is wrong. I forgot to update when moving Maven around. I change it to
C:\Dev\apache-maven-3.8.6

Adding \bin to that doesn’t help.

I don’t know the PATH variable.

The Maven readme says :
“set PATH="c:\program files\apache-maven-3.x.y\bin";%PATH%”

I don’t know what the %PATH% at the end means. I suspect it means adding c:\ etcetera to in front of what is already there.

I again set MAVEN_HOME to C:\Dev\apache-maven-3.8.6

I ask google how to add a value to the PATH for Windows.
There is no PATH variable.
There is a Path variable (see OP; I have removed the last % from %MAVEN_HOME%\bin%), but I don’t know what I am supposed to fill in there and I don’t get the fancy table.
So I create a PATH variable, that I set to value %MAVEN_HOME%\bin.

I instruct
mvn --version

Something extraordinary happened. It worked!
Maven home: C:\Dev\apache-maven-3.8.6
Java version: 18.0.2.1, vendor: Oracle Corporation, runtime: C:\Program Files\Java\jdk-18.0.2.1
Default locale: nl_BE, platform encoding: UTF-8
OS name: "windows 10", version: "10.0", arch: "amd64", family: "windows"
'cmd' is not recognized as an internal or external command,
operable program or batch file.

In Environment Variables, the Path variable has vanished! (I new there had to be a catch.) Java still works for some reason, but I suspect I’ll run into trouble later.
How can Java work without its path being in the PATH variable ?

I set the PATH variable to be
%JAVA_HOME%\bin;%MAVEN_HOME%\bin;TRICENTIS_SEARCH% ;%SystemRoot%\system32;%SystemRoot%;%SystemRoot%\S ystem32\Wbem;%SYSTEMROOT%\System32\WindowsPowerShe ll\v1.0\;%SYSTEMROOT%\System32\OpenSSH\;C:\Program Files\Java\jdk-18.0.2.1\bin;C:\Program Files (x86)\dotnet\;C:\Program Files\dotnet\;

mvn –version still works

I remove C:\Program Files\Java\jdk-18.0.2.1\bin from the PATH variable (as it seems a double of %JAVA_HOME%\bin).

Yes, but I still don’t understand why Java worked without the path having been indicated in the PATH variable.

Further, I keep following along with the instructions of the Pluralsight course ‘Maven Fundamentals’.

Program : Spring Tool Suite 4
Directory : C:\Users\Knarf\Documents\School\Informatica\Worksp aces\Spring Tool Suite workspace
In there is a project is created with folders \HelloWorld\src\main\java

In HelloWorld : .project and pom.xml
In java : HelloWorld.java

pom.xml :

<project>
	<groupId>com.pluralsight</groupId>
	<artifactId>HelloWorld</artifactId>
	<version>1.0-SNAPSHOT</version>
	<model>4.0.0</model>
	<packaging>jar</packaging>
</project>

HelloWorld.java :

public class HelloWorld {
	public static void main(String[] args) {
		system.out.println("Hello world!") ;
	}	
}

The teacher says to run mvn clean and then good stuff would happen.

When I instruct
mvn clean
I get
[INFO] Scanning for projects...
[ERROR] [ERROR] Some problems were encountered while processing the POMs:
[ERROR] Malformed POM C:\Users\Knarf\Documents\School\Informatica\Worksp aces\Spring Tool Suite workspace\HelloWorld\pom.xml: Unrecognised tag: 'model' (position: START_TAG seen ...</version>\r\n\t<model>... @5:9) @ C:\Users\Knarf\Documents\School\Informatica\Worksp aces\Spring Tool Suite workspace\HelloWorld\pom.xml, line 5, column 9
[ERROR] 'modelVersion' is missing. @ line 1, column 9
[ERROR] 'modelVersion' is missing. @ line 1, column 9
<etcetera>

In STS 4, in the pom file there is a red x at line one and a underlining of the closing bracket as if something extra is needed between project and >. Hovering over the red x says :
“Multiple annotations found at this line :
- No grammar constraints (DTD or XML Schema).
- ‘modelVersion’ is missing.”

At line 5 (<model>4.0.0</model>) there is a warning that looks the same as the ‘ Malformed POM C:\Users\K‘ error line (the 3rd) in the command prompt.

I found suggestions online about replacing <project> with

<?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 http://maven.apache.org/maven-v4_0_0.xsd">

but that doesn’t improve matters.

How can I get the clean command to do good stuff with that project ?

Is there on this forum a good place to ask about Maven and if so, where ?

Originally Posted by Norm

The program provided the full path to the java.exe command so that the OS could find it.

What program provided that path ?

The Command prompt was executing when commands starting with java worked.

I am in C:\Users\Knarf>

I removed %JAVA_HOME%\bin from the PATH variable.
Yet the command java --version still works.

I also removed %MAVEN_HOME%\bin from the PATH variable.
The command mvn --version still works.

I put them both back and give the variable JAVA_HOME and MAVEN_HOME a wrong value.
Yet both commands still work.

When I restart the Command Prompt, neither work.
So, I correct them.
Neither still work.
So, I restart the Command Prompt.
Problem solved.

Next, I remove %JAVA_HOME%\bin from PATH and restart the Command Prompt.
Java –version doesn’t work anymore;

That probably explains why I had trouble with the mvn command before. I had to restart the Command Prompt before changes to the path would take effect.