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mvn could not find or load main class org.codehaus.plexus.classworlds.launcher.launcher [duplicate]

I have installed a latest maven-3.0.4 on Windows 7:
The installation details are as follows:
Installation Path :
C:\apache-maven-3.0.4
Environment Variables are:
M2_HOME C:\apache-maven-3.0.4\apache-maven\src
JAVA_HOME C:\Program Files\Java\jdk-1.7.0_04
Path variables added are:
%M2_HOME%\bin;%JAVA_HOME%\bin;
In the command window it shows it like this:
C:\>java -version
java version "1.7.0_04"
Java(TM) SE Runtime Environment (build 1.7.0_04-b22)
Java HotSpot(TM) Client VM (build 23.0-b21, mixed mode, sharing)
C:\>mvn -version
Error: Could not find or load main class org.codehaus.plexus.classworlds.launcher.Launcher
This is the only version on maven installed on my PC and the solution given on many blogs referring to the deletion of the previous M2_HOME environment variable is not valid.
I have read and tried all the solutions given at blogs such as :
oracle blog,
stackoverflow question,
another stack question,
some blog,
But I'm still not able to get to it. What I might be missing in this whole thing?

I hit this problem too, and found this article. For Maven3, changing my environment variable name from M2_HOME to M3_HOME did the trick. I am on a Mac running OSX 10.9 with JDK 1.7.
Note: Please delete M2_HOME, if already set. Eg: unset M2_HOME.

Even though the question is answered I would like to add that, if you are getting the above mentioned error, be sure that you have downloaded the Binary file.
The source file should only be downloaded if you are an advanced user and that you know how to deal with it.
I have had quite a share of people downloading the wrong file, seniors and juniors

I was having this same problem and was able to resolve it by carefully redoing the Environment Variables:
M2_HOME
M2
JAVA_HOME
Also, I made them all System Variables, not User Variables like the Maven instructions say. When you
echo %Path%
Make sure you can see the %M2% and %JAVA_HOME% variables completely expanded, i.e. :
C:\Users\afairchild>echo %Path%
C:\Program Files\Apache Software Foundation\apache-maven-3.0.4\bin;C:\Program Files\Java\jdk1.7.0_09\bin; [etc]

I believe this error caused because of downloading SRC instead of BINARY from Maven site. Please make sure to download Binary zip.
Because the below path, you will get only when you download SRC:
M2_HOME C:\apache-maven-3.0.4\apache-maven\src

Had this issue on two different Ubuntu 12.04 installs, despite the installs being done by apt-get. Issue was M2_HOME.
Fixed with:
export M2_HOME=/usr/share/maven

It sounds like you installed (extracted) the source files instead of the binaries based on your path information. Try installing the binaries instead and following the other posters answer.

Well, I had this problem and after seeing this post and particularly khmarbaise answer I noticed that M2_HOME was
D:\workspace\apache-maven-3.1.0-bin\apache-maven-3.1.0\bin
and then I chaged it to
D:\workspace\apache-maven-3.1.0-bin\apache-maven-3.1.0
I would like to mention that I use windows 7 (x64)

The solution for later versions of Maven is straight-forward. I am on OS X ElCap, 10.11.6 and upgraded to Maven 3.3.9. I had the same problem with error "Could not find ...org.codehaus.plexus...". The link provided here offered the solution in a comment by McKamey - simply delete M2_HOME (unset M2_HOME). Once I tried that, it all worked as expected.
This can be confirmed by visiting the Maven install page: "Add the bin directory of the created directory apache-maven-3.3.9 to the PATH environment variable" -- no mention of M2_HOME or M3_HOME at all.

For most of the Maven setup issues something like "Could not find or load main class...", start-with below steps to see if that fixes:
Make sure you unzipped the right archive (BINARY archive and not SOURCE archive)
Remove all user and system variables related to Maven (ex. M2_HOME,M2_OPTS etc.)
Make sure JAVA_HOME system variable is setup (ex. "C:\Program Files\Java\jdk1.8.0_172")
Make sure java bin location is added in "path" system variable (ex. "%JAVA_HOME%\bin")
Make sure maven bin location is added in "path" system variable (ex. "C:\MyInstalls\apache-maven-3.5.4\bin")
then...
Verify java is setup (at commandprompt : java -version)
Verify maven is setup (at commandprompt : mvn --version)

Open a new terminal and do the followin
M2_HOME=/Users/macbook/apache-maven-3.6.1 //Set where maven is
M2=$M2_HOME/bin //Set home as bin
export PATH=$M2:$PATH //Place the new path
Then type
mvn -version
You can set this in ./bash_profile to do it automatically each time you run the terminal

You should change the location of the M2_HOME into the following:
set M2_HOME=C:\apache-maven-3.0.4\apache-maven
Furthermore the installation of the JDK looks more a JRE instead of JDK. For Maven you need JDK and NOT JRE.

I came across a similar problem on my mac OSX. After a series of trial and error attempts I finally resolved it.
My ~/.bash_profile looked like this
export M2_HOME=/Users/xyz/maven-3.x/bin
export PATH=$PATH:$M2_HOME
and when I tried to echo M2_HOME from the terminal, it showed me the correct path but when I tried to fire any maven command like mvn clean or mvn install, it always gave the same problem
Could not find or load main class org.codehaus.plexus.classworlds.launcher.Launcher
I solved this issue by changing my M2_HOME to this
export M2_HOME=/Users/xyz/maven-3.x
export PATH=$PATH:$M2_HOME/bin
And voila ! It started working ! Just by moving the position of /bin from M2_HOME to in front of the PATH

Just make sure you've downloaded Binary zip archive(apache-maven-3.5.0-bin.zip) instead of Source zip archive. Then add the bin directory of the created directory apache-maven-3.5.0 to the PATH environment variable.

install binary version of maven fixes the issues
apache-maven-3.6.1-bin.zip

I had the same issue. I have Windows xp box and when I would type mvn -version at the command line prompt I got the dreaded error message
"Exception in thread "main" java.lang.NoClassDefFoundError: org/codehaus/plexus/classworlds/launcher/Launcher"
I confirmed that my M2_HOME variable was set to the path where Maven was installed on pc and that the echo %path% confirmed that Maven was in my path.
I have been searching for a solution for hours when I stumbled on to my solution (I say my solution because I know this probably won't be the solution for everyone that is getting the same error).
I copied the path that was assigned to my M2_HOME variable. I opened a cmd window and typed cd and pasted the path I got from my M2_HOME variable. At that point I knew that the path was correct because the path was displayed in the window. At this point I entered the dir command and to my surprise, I got the error File Not Found.
I went to that path via Explorer and sure enough there were files present. I noticed that the folders were faded out, but I could access them and see the files within each folder (I have admin rights on my pc). I looked at the properties of the parent folder for Maven and saw that the Hidden box was checked. I removed the check and applied and tried my dir command again with success.
Next I tried the mvn –version command again, but this time I got back the expected results.
C:\>mvn -version
Apache Maven 3.0.3 (r1075438; 2011-02-28 11:31:09-0600)
Maven home: C:\Program Files\apache-maven-3.0.3
Java version: 1.5.0_16, vendor: Sun Microsystems Inc.
Java home: C:\Java\jdk1.5.0_16\jre
Default locale: en_US, platform encoding: Cp1252
OS name: "windows xp", version: "5.1", arch: "x86", family: "windows"
Finally I created a jar and war file and my web app ran successfully on my local Tomcat.
I hope this helps some of you out there.

Besides what #khmarbaise has pointed out, I think you have mistyped your JAVA_HOME. If you have installed in the default location, then there should be no "-" (hyphen) between jdk and 1.7.0_04. So it would be
JAVA_HOME C:\Program Files\Java\jdk1.7.0_04

For other people who might run into this, don't forget to check ~/.mavenrc for M2_HOME or JAVA_HOME settings.

Try to download binary zip (for ex. Maven 3.0.5 (Binary zip)) instead of complete source in official maven site.
Also make sure that command line recognizes java and javac commands.
I noticed that Maven Source zip didn't include any libraries at lib folder however Binary zip had them + in boot folder it had plexus-classworlds-2.4.jar. Perhaps the problem was with the absence of these libraries. Anyway it helped me so my M2_HOME is: C:\Program Files\Java\apache-maven-3.0.5 and at PATH I put: C:\Program Files\Java\apache-maven-3.0.5\bin.

I find this issue in my centOS is caused by "Oracle Java is replace by gcj", after change default java to "Oracle Java", the issue is resolved.
alternatives --config java
There are 2 programs which provide 'java'.
Selection Command
-----------------------------------------------
* 1 /usr/lib/jvm/jre-1.5.0-gcj/bin/java
+ 2 /usr/java/jdk1.7.0_67/bin/java

It look like that you have installed Source files(Because src only comes in Source Files and we don't need it). Try to install Binary Files from
there.
And then set environment variables as described
there.
This worked for me. And I am sure it will also work for you.

I think you download the wrong version.
I meet this problem just now, no method work after searching and searching.
Finally, I found that maven I downloaded is Source zip archive.
After I change to Binary zip archive, everything go to be fine.

Me too faced the similar issue. But in my case I used apache-maven-3.3.3-src folder in path variables. Later I corrected those with correct path of folder apache-maven-3.3.3-bin. This resolved the issue. Am not telling that is the same error reported here but this way also you can get this error and rectify it. That is what I am trying to say here.

Exactly the same error may appear even with correct environment variable settings, if you copy ONLY bin directory to the installation directory.
It make which work finely, and novices get stuck.

Next to the maybe useful, but maybe too symptomatic answers, here is one which tries to help to find the cause of the problem.
Maven is a command-line java tool. That means, it is not a standalone binary, it is a collection of java .jars, interpreted by a jvm (java.exe on windows, java on linux).
The mvn command, is a script. On windows, it is a script called mvn.cmd and on linux, it is a shell script. Thus, if you write: mvn install, what will happen:
a command interpreter (/bin/sh or cmd.exe) is called for the actual invoking script
this script sets the needed environment variables
and finally, it calls a java interpreter with the the required classpath which contain the maven functionality.
The problem is with (2). Fortunately, this script is simply, very simple. For a java programmer it shouldn't be a big trouble to debug a script around 20 lines, even if it is a little bit alien language.
On linux, you can debug shellscripts giving the -x flag to your shell interpreter (which is most probably bash). On windows, you have to find some other way to debug a cmd.exe script. So, instead of mvn install, give the command bash -x mvn install.
The result be like:
+ '[' -z '' ']'
+ '[' -f /etc/mavenrc ']'
+ '[' -f /home/picsa/.mavenrc ']'
+ cygwin=true
+ darwin=false
...not so many things...
+ MAVEN_PROJECTBASEDIR='C:\peter\bin'
+ export MAVEN_PROJECTBASEDIR
+ MAVEN_CMD_LINE_ARGS=' '
+ export MAVEN_CMD_LINE_ARGS
+ exec '/cygdrive/c/Program Files/Java/jdk1.8.0_66/bin/java' -classpath 'C:\peter/boot/plexus-classworlds-*.jar' '-Dclassworlds.conf=C:\peter/bin/m2.conf' '-Dmaven.home=C:\peter' '-Dmaven.multiModuleProjectDirectory=C:\peter\bin' org.codehaus.plexus.classworlds.launcher.Launcher
Fehler: Hauptklasse org.codehaus.plexus.classworlds.launcher.Launcher konnte nicht gefunden oder geladen werden
At the end, you can easily test, which environment variable gone bad, and you can very easily fix your script (or set it what is needed).

I had this problem when I used Maven 3.5.4 on OpenJDK 11 on Ubuntu. The OpenJDK 11 on Ubuntu is actually still a JDK10:
$ ls -al /etc/alternatives/java
lrwxrwxrwx 1 root root 43 Aug 24 04:54 /etc/alternatives/java -> /usr/lib/jvm/java-11-openjdk-amd64/bin/java
$ java --version
openjdk 10.0.2 2018-07-17
OpenJDK Runtime Environment (build 10.0.2+13-Ubuntu-1ubuntu0.18.04.3)
OpenJDK 64-Bit Server VM (build 10.0.2+13-Ubuntu-1ubuntu0.18.04.3, mixed mode)
I installed OpenJDK from Oracle into /opt/jdk-11.0.1 and run Maven like this:
JAVA_HOME=/opt/jdk-11.0.1 mvn
It now works like a charm.

I had a problem with surefire plugin itself. Going back to version 2.6 worked for me. Version 2.18/20/22.1 gave me the error.
Now I tried version 3.0.0-M1 of surefire plugin and it works.
So something is wrong in surefire plgin between version 2.6 and 3.0.0. I assume there is something hardcoded as default which should not.

For me, funny as it sounds, it helped just restarting eclipse...

This worked for me:
Remove all Mavin references in Environment Variables
Download the Binary from mavin
Unzip it to where you'd like ex: C:\apache-maven-3.6.0
Go to Environment variables and add to System variable path "C:\apache-maven-3.6.0\bin"
start command prompt as Administrator
check version with: mvn -v
CMD Result:
Apache Maven 3.6.0 (97c98ec64a1fdfee7767ce5ffb20918da4f719f3; 2018-10-24T20:41:47+02:00)
Maven home: C:\apache-maven-3.6.0\bin..

I also faced the following Error in my system (Mac)
Error: Could not find or load main class org.codehaus.plexus.classworlds.launcher.Launcher
After doing some random browsing, I came across the link "http://maven.apache.org/install.html" that says "JAVA_HOME" should be set to "/Library/Java/JavaVirtualMachines/jdk1.8.0_45.jdk/Contents/Home/jre".
When I changed "JAVA_HOME" as stated above in ".bash_profile", "mvn" command started working but "javac -version" command stopped working.
When I typed "javac -version" command, I got the following error
Unable to locate an executable at "/Library/Java/JavaVirtualMachines/jdk1.8.0_45.jdk/Contents/Home/jre/bin/javac" (-1)
Hence I rolled back my "JAVA_HOME" to "/Library/Java/JavaVirtualMachines/jdk1.8.0_45.jdk/Contents/Home" in ".bash_profile" and added the following line at the top in "mvn" script
export JAVA_HOME=/Library/Java/JavaVirtualMachines/jdk1.8.0_45.jdk/Contents/Home/jre
Now both "mvn" and "javac" commands worked properly, but after careful observation of the mvn script, I could not make the difference between the following commands
/Library/Java/JavaVirtualMachines/jdk1.8.0_45.jdk/Contents/Home/bin/java -classpath /Users/venkatarajeevmandava/Documents/Maven/apache-maven-3.6.1/boot/plexus-classworlds-2.6.0.jar -Dclassworlds.conf=/Users/venkatarajeevmandava/Documents/Maven/apache-maven-3.6.1/bin/m2.conf -Dmaven.home=/Users/venkatarajeevmandava/Documents/Maven/apache-maven-3.6.1 -Dlibrary.jansi.path=/Users/venkatarajeevmandava/Documents/Maven/apache-maven-3.6.1/lib/jansi-native -Dmaven.multiModuleProjectDirectory=/Users/venkatarajeevmandava/Documents/Maven/apache-maven-3.6.1/bin org.codehaus.plexus.classworlds.launcher.Launcher
/Library/Java/JavaVirtualMachines/jdk1.8.0_45.jdk/Contents/Home/jre/bin/java -classpath /Users/venkatarajeevmandava/Documents/Maven/apache-maven-3.6.1/boot/plexus-classworlds-2.6.0.jar -Dclassworlds.conf=/Users/venkatarajeevmandava/Documents/Maven/apache-maven-3.6.1/bin/m2.conf -Dmaven.home=/Users/venkatarajeevmandava/Documents/Maven/apache-maven-3.6.1 -Dlibrary.jansi.path=/Users/venkatarajeevmandava/Documents/Maven/apache-maven-3.6.1/lib/jansi-native -Dmaven.multiModuleProjectDirectory=/Users/venkatarajeevmandava/Documents/Maven/apache-maven-3.6.1/bin org.codehaus.plexus.classworlds.launcher.Launcher
In the above the first command caused the following error
Error: Could not find or load main class org.codehaus.plexus.classworlds.launcher.Launcher
while the second command worked fine.
Please Note that both the above paths have "java" command while one is from "jre" the other is from "jdk"
Other global variables are as following in ".bash_profile"
export M2_HOME=/Users/venkatarajeevmandava/Documents/Maven/apache-maven-3.6.1
export PATH=$PATH:$M2_HOME/bin

Was able to solve this issue by deleting the downloaded maven in my machine ( /Users/kkohli/Desktop/Personal/Code/Java/apache-maven-3.6.3 ) and re-downloading the binary version from the apache site. Did not modify any other bashprofile file etc ( My M2_HOME, JAVA_HOME etc are set inside my bashprofile)

Oracle SqlDeveloper JDK path

I have recently installed sqldeveloper but i'm getting the below warning window when I try to launch it. This is causing the sqldeveloper to run very very slow and it hangs frequently
I have tried editing the file sqldeveloper.cong as suggested in the window above but does not work
Original
SetJavaHome ../../jdk
Update 1
SetJavaHome C:\Program Files\Java\jdk1.7.0_60\bin\ and all other variations but still getting the above warning window
Update 2
SetJavaHome C:\Program Files (x86)\Java\jre7\bin and all other variations
Please suggest the correct way

The message seems to be out of date. In version 4 that setting exists in two files, and you need to change it in the other one, which is:
%APPDATA%\sqldeveloper\1.0.0.0.0\product.conf
Which you might need to expand to your actual APPDATA, which will be something like C:\Users\cprasad\AppData\Roaming. In that file you will see the SetJavaHome is currently going to be set to the path to your Java 1.8 location, so change that as you did in the sqldeveloper.conf:
SetJavaHome C:\Program Files\Java\jdk1.7.0_60\bin\
If the settig is blank (in both files, I think) then it should prompt you to pick the JDK location when you launch it, if you prefer.

another thing you could try is to rename your old jdk folder, lets say its:
C:\Program Files\Java\jdk1.7.0_04
change it to saomething like:
C:\Program Files\Java\xxxjdk1.7.0_04
Now, you should once again asked to set your jdk folder location on Oracle SqlDeveloper launch, and you can chose the right path.
Not the most elegant solution, but it worked for me.
Milos

In your SQL Developer Bin Folder find
\sqldeveloper\bin\sqldeveloper.conf
It should be
SetJavaHome \path\to\jdk
You said it was ../../jdk originally so you could ultimatey do 1 of two things:
SetJavaHome C:\Program Files\Java\jdk1.7.0_60
This is assuming that you have JDK 1.7.60 installed in that directory; you don't want to point it to the bin folder you want the whole JDK folder.
OR
The second thing you can do is find the jdk folder in the sqldeveloper folder for me its sqldeveloper\jdk and copy and paste the contents from C:\Program Files\Java\jdk1.7.0_60. You then have to revert your change to read
SetJavaHome ../../jdk
in your sqldeveloper.conf
If all else fails you can always redownload the sqldeveloper that already contains the jdk7 all zipped up and ready for you to run at will: Download SQL Developer The file I talk about is called Windows 64-bit - zip file includes the JDK 7

I cannot believe Oracle's documentation is SO LAME! In some documents it is misleading people to point to the JDK by specifying the path to the JDK root, e.g. on a Mac:
/Library/Java/JavaVirtualMachines/jdk1.8.0_151.jdk/
Reviewing /Applications/SQLDeveloper.app/Contents/MacOS/sqldeveloper.sh
revealed the method they use to set up the path:
TMP_PATH=/usr/libexec/java_home -F -v 9
if [ -z "$TMP_PATH" ] ; then
TMP_PATH=/usr/libexec/java_home -F -v 1.8
if [ -z "$TMP_PATH" ] ; then
osascript -e 'tell app "System Events" to display dialog "SQL Developer requires a minimum of Java 8. \nJava 8 can be downloaded from:\n http://www.oracle.com/technetwork/java/javase/downloads/"'
exit 1
fi
fi
Executing this manually from Terminal:
/usr/libexec/java_home -F -v 1.8
Lists the path as:
/Library/Java/JavaVirtualMachines/jdk1.8.0_152.jdk/Contents/Home
And this is what you need to specify as the value for
SetJavaHome /Library/Java/JavaVirtualMachines/jdk1.8.0_152.jdk/Contents/Home
Thank you Oracle for wasting half a day on your "product" that does NOT even support your latest Java version, also released by you.

On Windows,Close all the SQL Developer windows. Then You need to completely delete the SQL Developer and sqldeveloper folders located in user/AppData/Roaming. Finally, run the program, you will be prompted for new JDK.
Note that AppData is a hidden folder.

For those who use Mac, edit this file:
/Applications/SQLDeveloper.app/Contents/MacOS/sqldeveloper.sh
Mine had:
export JAVA_HOME=`/usr/libexec/java_home -v 1.7`
and I changed it to 1.8 and it stopped complaining about java version.

if you use sqldeveloper 18.2.0
edit %APPDATA%\sqldeveloper\18.2.0\product.conf
jdk9, jdk10, and jdk11 are not supported
change back to jdk 8
for example
SetJavaHome C:\Program Files\ojdkbuild\java-1.8.0-openjdk-1.8.0.191-1

Cannot get Maven working on Windows 7 [duplicate]

I just installed Maven and added the \bin directory of maven to my path variables. When I try to use the mvn command in the Command Prompt I just get a message:
mvn: command not found
Everything else I found on here did not help yet.
Edit:
I used https://maven.apache.org/install.html to install maven.
SET PATH=%PATH%;C:\Program Files\Maven\apache-maven-3.5.0\bin\mvn.cmd
PATHEXT=.COM;.EXE;.BAT;.CMD;.VBS;.VBE;.JS;.JSE;.WSF;.WSH;.MSC

You have included the file in the path:
C:\Program Files\Maven\apache-maven-3.5.0\bin\mvn.cmd
That is not good. The PATH environment variable should only include a path to where files, like exe and cmd's can be found.
Adapt your PATH to read like this:
C:\Program Files\Maven\apache-maven-3.5.0\bin
(so remove the \mvn.cmd). Make sure to start a new command prompt to verify if your path settings are correct.
See How can I set user environmental variables (such as PATH) from a non-administrator account on Windows 7 to find the correct Windows dialog to adapt the settings among many more.

Following this tutorial by mkyong, I was able to get this to work on Windows 10 (v10.0.15063):
Install JDK and setup JAVA_HOME system variable
Download Maven zip, extract it and setup M2_HOME and MAVEN_HOME system variables to point to root maven folder (without \bin)
Update PATH system variable to include %M2_HOME%\bin (this is what will let you run "mvn" in Command Prompt).
Open Command Prompt (cmd.exe) and execute mvn -version
You can download Maven (apache-maven-3.5.0-bin.zip) here, if you don't have it already.
The Java SDK (jdk-8u144-windows-x64.exe) can be downloaded from Oracle here.

This is my working maven configuration on Windows 10. Was more cumbersome to configure on W10 than on WXP or W7.

I've faced the same problem. I installed Maven and added the \bin directory of maven to my path variables in System Variables, so I can only use MAVEN commands using admin rights (run cmd in windows as administrator)
I solved this by creating all under User variables (including the PATH variable).

Maven error: Could not find or load main class org.codehaus.plexus.classworlds.launcher.Launcher

I have installed a latest maven-3.0.4 on Windows 7:
The installation details are as follows:
Installation Path :
C:\apache-maven-3.0.4
Environment Variables are:
M2_HOME C:\apache-maven-3.0.4\apache-maven\src
JAVA_HOME C:\Program Files\Java\jdk-1.7.0_04
Path variables added are:
%M2_HOME%\bin;%JAVA_HOME%\bin;
In the command window it shows it like this:
C:\>java -version
java version "1.7.0_04"
Java(TM) SE Runtime Environment (build 1.7.0_04-b22)
Java HotSpot(TM) Client VM (build 23.0-b21, mixed mode, sharing)
C:\>mvn -version
Error: Could not find or load main class org.codehaus.plexus.classworlds.launcher.Launcher
This is the only version on maven installed on my PC and the solution given on many blogs referring to the deletion of the previous M2_HOME environment variable is not valid.
I have read and tried all the solutions given at blogs such as :
oracle blog,
stackoverflow question,
another stack question,
some blog,
But I'm still not able to get to it. What I might be missing in this whole thing?

I hit this problem too, and found this article. For Maven3, changing my environment variable name from M2_HOME to M3_HOME did the trick. I am on a Mac running OSX 10.9 with JDK 1.7.
Note: Please delete M2_HOME, if already set. Eg: unset M2_HOME.

Even though the question is answered I would like to add that, if you are getting the above mentioned error, be sure that you have downloaded the Binary file.
The source file should only be downloaded if you are an advanced user and that you know how to deal with it.
I have had quite a share of people downloading the wrong file, seniors and juniors

I was having this same problem and was able to resolve it by carefully redoing the Environment Variables:
M2_HOME
M2
JAVA_HOME
Also, I made them all System Variables, not User Variables like the Maven instructions say. When you
echo %Path%
Make sure you can see the %M2% and %JAVA_HOME% variables completely expanded, i.e. :
C:\Users\afairchild>echo %Path%
C:\Program Files\Apache Software Foundation\apache-maven-3.0.4\bin;C:\Program Files\Java\jdk1.7.0_09\bin; [etc]

I believe this error caused because of downloading SRC instead of BINARY from Maven site. Please make sure to download Binary zip.
Because the below path, you will get only when you download SRC:
M2_HOME C:\apache-maven-3.0.4\apache-maven\src

Had this issue on two different Ubuntu 12.04 installs, despite the installs being done by apt-get. Issue was M2_HOME.
Fixed with:
export M2_HOME=/usr/share/maven

It sounds like you installed (extracted) the source files instead of the binaries based on your path information. Try installing the binaries instead and following the other posters answer.

Well, I had this problem and after seeing this post and particularly khmarbaise answer I noticed that M2_HOME was
D:\workspace\apache-maven-3.1.0-bin\apache-maven-3.1.0\bin
and then I chaged it to
D:\workspace\apache-maven-3.1.0-bin\apache-maven-3.1.0
I would like to mention that I use windows 7 (x64)

The solution for later versions of Maven is straight-forward. I am on OS X ElCap, 10.11.6 and upgraded to Maven 3.3.9. I had the same problem with error "Could not find ...org.codehaus.plexus...". The link provided here offered the solution in a comment by McKamey - simply delete M2_HOME (unset M2_HOME). Once I tried that, it all worked as expected.
This can be confirmed by visiting the Maven install page: "Add the bin directory of the created directory apache-maven-3.3.9 to the PATH environment variable" -- no mention of M2_HOME or M3_HOME at all.

For most of the Maven setup issues something like "Could not find or load main class...", start-with below steps to see if that fixes:
Make sure you unzipped the right archive (BINARY archive and not SOURCE archive)
Remove all user and system variables related to Maven (ex. M2_HOME,M2_OPTS etc.)
Make sure JAVA_HOME system variable is setup (ex. "C:\Program Files\Java\jdk1.8.0_172")
Make sure java bin location is added in "path" system variable (ex. "%JAVA_HOME%\bin")
Make sure maven bin location is added in "path" system variable (ex. "C:\MyInstalls\apache-maven-3.5.4\bin")
then...
Verify java is setup (at commandprompt : java -version)
Verify maven is setup (at commandprompt : mvn --version)

Open a new terminal and do the followin
M2_HOME=/Users/macbook/apache-maven-3.6.1 //Set where maven is
M2=$M2_HOME/bin //Set home as bin
export PATH=$M2:$PATH //Place the new path
Then type
mvn -version
You can set this in ./bash_profile to do it automatically each time you run the terminal

You should change the location of the M2_HOME into the following:
set M2_HOME=C:\apache-maven-3.0.4\apache-maven
Furthermore the installation of the JDK looks more a JRE instead of JDK. For Maven you need JDK and NOT JRE.

I came across a similar problem on my mac OSX. After a series of trial and error attempts I finally resolved it.
My ~/.bash_profile looked like this
export M2_HOME=/Users/xyz/maven-3.x/bin
export PATH=$PATH:$M2_HOME
and when I tried to echo M2_HOME from the terminal, it showed me the correct path but when I tried to fire any maven command like mvn clean or mvn install, it always gave the same problem
Could not find or load main class org.codehaus.plexus.classworlds.launcher.Launcher
I solved this issue by changing my M2_HOME to this
export M2_HOME=/Users/xyz/maven-3.x
export PATH=$PATH:$M2_HOME/bin
And voila ! It started working ! Just by moving the position of /bin from M2_HOME to in front of the PATH

Just make sure you've downloaded Binary zip archive(apache-maven-3.5.0-bin.zip) instead of Source zip archive. Then add the bin directory of the created directory apache-maven-3.5.0 to the PATH environment variable.

install binary version of maven fixes the issues
apache-maven-3.6.1-bin.zip

I had the same issue. I have Windows xp box and when I would type mvn -version at the command line prompt I got the dreaded error message
"Exception in thread "main" java.lang.NoClassDefFoundError: org/codehaus/plexus/classworlds/launcher/Launcher"
I confirmed that my M2_HOME variable was set to the path where Maven was installed on pc and that the echo %path% confirmed that Maven was in my path.
I have been searching for a solution for hours when I stumbled on to my solution (I say my solution because I know this probably won't be the solution for everyone that is getting the same error).
I copied the path that was assigned to my M2_HOME variable. I opened a cmd window and typed cd and pasted the path I got from my M2_HOME variable. At that point I knew that the path was correct because the path was displayed in the window. At this point I entered the dir command and to my surprise, I got the error File Not Found.
I went to that path via Explorer and sure enough there were files present. I noticed that the folders were faded out, but I could access them and see the files within each folder (I have admin rights on my pc). I looked at the properties of the parent folder for Maven and saw that the Hidden box was checked. I removed the check and applied and tried my dir command again with success.
Next I tried the mvn –version command again, but this time I got back the expected results.
C:\>mvn -version
Apache Maven 3.0.3 (r1075438; 2011-02-28 11:31:09-0600)
Maven home: C:\Program Files\apache-maven-3.0.3
Java version: 1.5.0_16, vendor: Sun Microsystems Inc.
Java home: C:\Java\jdk1.5.0_16\jre
Default locale: en_US, platform encoding: Cp1252
OS name: "windows xp", version: "5.1", arch: "x86", family: "windows"
Finally I created a jar and war file and my web app ran successfully on my local Tomcat.
I hope this helps some of you out there.

Besides what #khmarbaise has pointed out, I think you have mistyped your JAVA_HOME. If you have installed in the default location, then there should be no "-" (hyphen) between jdk and 1.7.0_04. So it would be
JAVA_HOME C:\Program Files\Java\jdk1.7.0_04

For other people who might run into this, don't forget to check ~/.mavenrc for M2_HOME or JAVA_HOME settings.

Try to download binary zip (for ex. Maven 3.0.5 (Binary zip)) instead of complete source in official maven site.
Also make sure that command line recognizes java and javac commands.
I noticed that Maven Source zip didn't include any libraries at lib folder however Binary zip had them + in boot folder it had plexus-classworlds-2.4.jar. Perhaps the problem was with the absence of these libraries. Anyway it helped me so my M2_HOME is: C:\Program Files\Java\apache-maven-3.0.5 and at PATH I put: C:\Program Files\Java\apache-maven-3.0.5\bin.

I find this issue in my centOS is caused by "Oracle Java is replace by gcj", after change default java to "Oracle Java", the issue is resolved.
alternatives --config java
There are 2 programs which provide 'java'.
Selection Command
-----------------------------------------------
* 1 /usr/lib/jvm/jre-1.5.0-gcj/bin/java
+ 2 /usr/java/jdk1.7.0_67/bin/java

It look like that you have installed Source files(Because src only comes in Source Files and we don't need it). Try to install Binary Files from
there.
And then set environment variables as described
there.
This worked for me. And I am sure it will also work for you.

I think you download the wrong version.
I meet this problem just now, no method work after searching and searching.
Finally, I found that maven I downloaded is Source zip archive.
After I change to Binary zip archive, everything go to be fine.

Me too faced the similar issue. But in my case I used apache-maven-3.3.3-src folder in path variables. Later I corrected those with correct path of folder apache-maven-3.3.3-bin. This resolved the issue. Am not telling that is the same error reported here but this way also you can get this error and rectify it. That is what I am trying to say here.

Exactly the same error may appear even with correct environment variable settings, if you copy ONLY bin directory to the installation directory.
It make which work finely, and novices get stuck.

Next to the maybe useful, but maybe too symptomatic answers, here is one which tries to help to find the cause of the problem.
Maven is a command-line java tool. That means, it is not a standalone binary, it is a collection of java .jars, interpreted by a jvm (java.exe on windows, java on linux).
The mvn command, is a script. On windows, it is a script called mvn.cmd and on linux, it is a shell script. Thus, if you write: mvn install, what will happen:
a command interpreter (/bin/sh or cmd.exe) is called for the actual invoking script
this script sets the needed environment variables
and finally, it calls a java interpreter with the the required classpath which contain the maven functionality.
The problem is with (2). Fortunately, this script is simply, very simple. For a java programmer it shouldn't be a big trouble to debug a script around 20 lines, even if it is a little bit alien language.
On linux, you can debug shellscripts giving the -x flag to your shell interpreter (which is most probably bash). On windows, you have to find some other way to debug a cmd.exe script. So, instead of mvn install, give the command bash -x mvn install.
The result be like:
+ '[' -z '' ']'
+ '[' -f /etc/mavenrc ']'
+ '[' -f /home/picsa/.mavenrc ']'
+ cygwin=true
+ darwin=false
...not so many things...
+ MAVEN_PROJECTBASEDIR='C:\peter\bin'
+ export MAVEN_PROJECTBASEDIR
+ MAVEN_CMD_LINE_ARGS=' '
+ export MAVEN_CMD_LINE_ARGS
+ exec '/cygdrive/c/Program Files/Java/jdk1.8.0_66/bin/java' -classpath 'C:\peter/boot/plexus-classworlds-*.jar' '-Dclassworlds.conf=C:\peter/bin/m2.conf' '-Dmaven.home=C:\peter' '-Dmaven.multiModuleProjectDirectory=C:\peter\bin' org.codehaus.plexus.classworlds.launcher.Launcher
Fehler: Hauptklasse org.codehaus.plexus.classworlds.launcher.Launcher konnte nicht gefunden oder geladen werden
At the end, you can easily test, which environment variable gone bad, and you can very easily fix your script (or set it what is needed).

I had this problem when I used Maven 3.5.4 on OpenJDK 11 on Ubuntu. The OpenJDK 11 on Ubuntu is actually still a JDK10:
$ ls -al /etc/alternatives/java
lrwxrwxrwx 1 root root 43 Aug 24 04:54 /etc/alternatives/java -> /usr/lib/jvm/java-11-openjdk-amd64/bin/java
$ java --version
openjdk 10.0.2 2018-07-17
OpenJDK Runtime Environment (build 10.0.2+13-Ubuntu-1ubuntu0.18.04.3)
OpenJDK 64-Bit Server VM (build 10.0.2+13-Ubuntu-1ubuntu0.18.04.3, mixed mode)
I installed OpenJDK from Oracle into /opt/jdk-11.0.1 and run Maven like this:
JAVA_HOME=/opt/jdk-11.0.1 mvn
It now works like a charm.

I had a problem with surefire plugin itself. Going back to version 2.6 worked for me. Version 2.18/20/22.1 gave me the error.
Now I tried version 3.0.0-M1 of surefire plugin and it works.
So something is wrong in surefire plgin between version 2.6 and 3.0.0. I assume there is something hardcoded as default which should not.

For me, funny as it sounds, it helped just restarting eclipse...

This worked for me:
Remove all Mavin references in Environment Variables
Download the Binary from mavin
Unzip it to where you'd like ex: C:\apache-maven-3.6.0
Go to Environment variables and add to System variable path "C:\apache-maven-3.6.0\bin"
start command prompt as Administrator
check version with: mvn -v
CMD Result:
Apache Maven 3.6.0 (97c98ec64a1fdfee7767ce5ffb20918da4f719f3; 2018-10-24T20:41:47+02:00)
Maven home: C:\apache-maven-3.6.0\bin..

I also faced the following Error in my system (Mac)
Error: Could not find or load main class org.codehaus.plexus.classworlds.launcher.Launcher
After doing some random browsing, I came across the link "http://maven.apache.org/install.html" that says "JAVA_HOME" should be set to "/Library/Java/JavaVirtualMachines/jdk1.8.0_45.jdk/Contents/Home/jre".
When I changed "JAVA_HOME" as stated above in ".bash_profile", "mvn" command started working but "javac -version" command stopped working.
When I typed "javac -version" command, I got the following error
Unable to locate an executable at "/Library/Java/JavaVirtualMachines/jdk1.8.0_45.jdk/Contents/Home/jre/bin/javac" (-1)
Hence I rolled back my "JAVA_HOME" to "/Library/Java/JavaVirtualMachines/jdk1.8.0_45.jdk/Contents/Home" in ".bash_profile" and added the following line at the top in "mvn" script
export JAVA_HOME=/Library/Java/JavaVirtualMachines/jdk1.8.0_45.jdk/Contents/Home/jre
Now both "mvn" and "javac" commands worked properly, but after careful observation of the mvn script, I could not make the difference between the following commands
/Library/Java/JavaVirtualMachines/jdk1.8.0_45.jdk/Contents/Home/bin/java -classpath /Users/venkatarajeevmandava/Documents/Maven/apache-maven-3.6.1/boot/plexus-classworlds-2.6.0.jar -Dclassworlds.conf=/Users/venkatarajeevmandava/Documents/Maven/apache-maven-3.6.1/bin/m2.conf -Dmaven.home=/Users/venkatarajeevmandava/Documents/Maven/apache-maven-3.6.1 -Dlibrary.jansi.path=/Users/venkatarajeevmandava/Documents/Maven/apache-maven-3.6.1/lib/jansi-native -Dmaven.multiModuleProjectDirectory=/Users/venkatarajeevmandava/Documents/Maven/apache-maven-3.6.1/bin org.codehaus.plexus.classworlds.launcher.Launcher
/Library/Java/JavaVirtualMachines/jdk1.8.0_45.jdk/Contents/Home/jre/bin/java -classpath /Users/venkatarajeevmandava/Documents/Maven/apache-maven-3.6.1/boot/plexus-classworlds-2.6.0.jar -Dclassworlds.conf=/Users/venkatarajeevmandava/Documents/Maven/apache-maven-3.6.1/bin/m2.conf -Dmaven.home=/Users/venkatarajeevmandava/Documents/Maven/apache-maven-3.6.1 -Dlibrary.jansi.path=/Users/venkatarajeevmandava/Documents/Maven/apache-maven-3.6.1/lib/jansi-native -Dmaven.multiModuleProjectDirectory=/Users/venkatarajeevmandava/Documents/Maven/apache-maven-3.6.1/bin org.codehaus.plexus.classworlds.launcher.Launcher
In the above the first command caused the following error
Error: Could not find or load main class org.codehaus.plexus.classworlds.launcher.Launcher
while the second command worked fine.
Please Note that both the above paths have "java" command while one is from "jre" the other is from "jdk"
Other global variables are as following in ".bash_profile"
export M2_HOME=/Users/venkatarajeevmandava/Documents/Maven/apache-maven-3.6.1
export PATH=$PATH:$M2_HOME/bin

Was able to solve this issue by deleting the downloaded maven in my machine ( /Users/kkohli/Desktop/Personal/Code/Java/apache-maven-3.6.3 ) and re-downloading the binary version from the apache site. Did not modify any other bashprofile file etc ( My M2_HOME, JAVA_HOME etc are set inside my bashprofile)

How to install Apache Ant?

I want to install SMSlib (http://smslib.org/) in installation instruction (http://code.google.com/p/smslib/wiki/Installation).
In here I must install Apache Ant, but I didn't understand how to do that.
I already download Apache Ant 1.7.1 , read manual (http://ant.apache.org/manual/index.html)
In here I must have RPM version from jpackage.org right? I already go to http://www.jpackage.org/ after that what must I do? I already try (http://mirrors.dotsrc.org/jpackage/1.7/generic/free/repodata/) and (http://www.jpackage.org/browser/browse.php?jppversion=1.7) but too many link. I don't know witch one must I download

If you're on Windows, you can use WinAnt, a Windows installer for Apache Ant that I made.

Step 1: Download and install
Download Ant. Go to the Ant homepage and click to download the binary. Because we’re talking about Windows, choose to download the ZIP file rather than any of the others. Scroll down to where it says “Current release of Ant” and click on the ZIP filename.
Once downloaded, unzip the file. You’ll now need to choose a permanent home for Ant on the computer. c:\java\ant is often used, but you can put it wherever you want.
Step 2: Set environment variables
For Windows XP: To set environment variables on Windows XP, right click on My Computer and select Properties. Then go to the Advanced tab and click the Environment Variables button at the bottom.
For Windows 7: To set environment variables on Windows 7, right click on Computer and select Properties. Click on Advanced System Settings and click the Environment Variables button at the bottom.
The only environment variable that you absolutely need is JAVA_HOME, which tells Ant the location of your JRE.
If you’ve installed the JDK, this is likely
c:\Program Files\Java\jdk1.x.x\jre
on Windows XP and
c:\Program Files(x86)\Java\jdk1.x.x\jre
on Windows 7. You’ll note that both have spaces in their paths, which causes a problem. You need to use the mangled name[3] instead of the complete name. So for Windows XP, use C:\Progra~1\Java\jdk1.x.x\jre and for Windows 7, use C:\Progra~2\Java\jdk1.6.0_26\jre if it’s installed in the Program Files(x86) folder
That alone is enough to get Ant to work, but for convenience, it’s a good idea to add the Ant binary path to the PATH variable.
This variable is a semicolon-delimited list of directories to search for executables. To be able to run ant in any directory, Windows needs to know both the location for the ant binary and for the java binary. You’ll need to add both of these to the end of the PATH variable. For Windows XP, you’ll likely add something like this:
;c:\java\ant\bin;C:\Progra~1\Java\jdk1.x.x\jre\bin
For Windows 7, it will look something like this:
;c:\java\ant\bin;C:\Progra~2\Java\jdk1.x.x\jre\bin
Done
Once you’ve done that and applied the changes, you’ll need to open a new command prompt to see if the variables are set properly. You should be able to simply run ant and see something like this:
Buildfile: build.xml does not exist!
Build failed
That means Ant is installed properly and is looking for a build.xml file.
Source: http://www.nczonline.net/blog/2012/04/12/how-to-install-apache-ant-on-windows/

You can follow these instrunctions-
1)Download the latest version of ant from http://ant.apache.org/bindownload.cgi
2)Unzip and save it to your C:\ directory as ant.
3)Add the bin directory to your PATH environment variable.
4)Add the ANT_HOME environment variable set to C:\ant.
you can use following commands to set ANT_HOME variable
C:>set ANT_HOME=C:\ant
C:>set JAVA_HOME=C:\jdk
C:>set PATH=%ANT_HOME%\bin;%JAVA_HOME%\bin
C:>ant -version
Apache Ant version 1.8.1 compiled on April 30 2010
if you have java installed on your machine
5)Add the ANT_OPTS environment variable set to -Xmx256M.
This is all you need to install ant on your machine.

1) Download "apache-ant-1.8.4-bin.zip" from "http://ant.apache.org/bindownload.cgi"
2) Unzip it and copy "apache-ant-1.8.4" in "c:\Program Files"
3) Right Click "My Computer" -> properties -> Advanced -> Environment variables -> Edit variable "PATH" and append value "C:\Program Files\Java\jdk 1.7.0_04\bin;C:\Program Files\apache-ant-1.8.4\bin" and Click "OK".
4) open cmd and type "ant" for checking.

the installation of ant and smslib is pretty simple. All you need to do is extract it to some directory. Export the path in case of Linux or set the ANT_HOME\bin to the PATH variable to access it from any directory in the shell. ANT_HOME is the root directory where ant is installed.
For SMSLib Download the zip file and this link should guide you on a step by step basis

Sound's like you're using Linux. If so, the easiest way would be to use a package management frontend like Synaptic and install ant in there.

Its very simple just install Apache ant installer for windows give on [link][1]
[1]: http://code.google.com/p/winant/ and all is set.No need to set Environment variables.It will automatically do every thing for you.

You can install Apache Ant with only single command on Ubuntu:
sudo apt install ant
Check the version of ant installed with:
ant -version