I am developing a project which needs a client personal jar, and it needs to be deployed on a pipeline of tools which are out of our control (sadly). One of the tools in this pipeline is sonarqube.
To build and deploy we have to use maven.
I put the jar into a folder of the project, and tried various way to actually make it work.
The first (working) way was to have it as a system with a systemPath to the folder of the project. It compiled, worked and everything, but sonarqube apparently hates systemPath and made us take it away.
After a tiny bit of searching, we added to our pom a maven-install-plugin, bounded an install-file to validate phase and configured to generate the dependency. This seems to work on local if I first run mvn validate and THEN mvn clean package. Otherwise, it tries to look for the jar on the main repository and fails. If I comment the tag and leave only the plugin active, I noticed it executes the plugin, installs the jar to local repository, but build fails due to not resolving packages and classes inside the jar. If I now put the tag in, everything works, because it now find the jar in the repository.
While this solution works, it doesnt suite me because the repository will be emptied every once in a while, and to restart everything I would need to commits, one knownligly failing, just to install the jar.
I tried addind a tag instead, pointing to a project dir where I would store the necessary jar, and that works just fine on my PC, but utterly fails on the pipeline, looking at main repository only (I guess it is some configuration on the pipeline, but cant really tell, being outside my control)
Was actually able to do it with maven install plugin,
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-install-plugin</artifactId>
<configuration>
<groupId>com.exmaple.stuff</groupId>
<artifactId>ClientJar</artifactId>
<version>1.0</version>
<packaging>jar</packaging>
<file>${project.basedir}/src/main/resources/ClientJar-1.0.jar</file>
<generatePom>true</generatePom>
</configuration>
<executions>
<execution>
<id>install-client-jar</id>
<phase>validate</phase>
<goals>
<goal>install-file</goal>
</goals>
</execution>
</executions>
</plugin>
</plugins>
And having dependency
<!-- Client jar -->
<dependency>
<groupId>example</groupId>
<artifactId>ClientJar</artifactId>
<version>1.0</version>
</dependency>
If you notice, the tricky part here was actually that groupId is different between the dependency and the plugin declaration. I do not know if this difference is due to the configuration of their artifactory server, but it seems to work locally too.
Also it is needed to explicitly run mvn validate in the pipeline
I'm trying to work around a maven bug MDEP-187 ( https://issues.apache.org/jira/browse/MDEP-187 ) by not using workspace resolution.
This forces me to do a mvn install for all my dependencies, I'm doing this by creating a launch configuration in eclipse with goal install.
The problem is that i have to create a launch config for every project in my multiproject workspace, in addition to install i have to manually call every launch config and run it. Which just doesn't work.
Is it possible to automatically install a project in the local repository? (whenever i update my code)
If you don't need to run dependency:copy in Eclipse, you can use following work-around:
Add a profile to your pom.xml, something like this:
<profiles>
<profile>
<id>copy</id>
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-dependency-plugin</artifactId>
<version>2.10</version>
<executions>
[...]
</executions>
</plugin>
</plugins>
<build>
<profile>
</profiles>
Enable workspace resolution in Eclipse.
Then Eclipse will not use dependency:copy, but you can use dependency:copy with command line: mvn install -P copy.
I did go with #khmarbaise solution:
But than you need to can handle the whole thing via
maven-assembly-plugin which can create archives / folders with all the
dependencies. Apart from that a swing ui must be started somehow which
will need some kind of shell script / batch file which you can create
by using appassembler-maven-plugin...And it sounds like you need to go
for a multi module project in maven..cause you might have parts like
core, ui, etc. which are needed to be combined in the end.
#khmarbaise i was in the understanding that the assembly-plugin didn't
support putting dependencies in a lib/ folder (just putting everything
in 1 big jar), but after a little bit of trying i just go myself a zip
with a runnable jar and my dependencies in a lib/ folder. Tomorrow i'm
going to read a bit more about the assembly-plugin. I'm happy ;-
I have a program which runs as a Spring boot App in eclipse. The program was running fine. Then i did the following:
Right click on project -> Run As -> Maven Test .
This was accidental. When i then tried to run the program as a spring boot app again, it threw the following error below.
Error: Could not find or load main class com.bt.collab.alu.api.webapp.Application
How do i point the application back to my main class?
Thanks
I had the same problem. Try this :
Right Click the project -> Maven -> Update Project
Then Re-run the project. Hope it work for you too.
Main class is configurable in pom.xml
<properties>
<start-class>com.bt.collab.alu.api.webapp.Application</start-class>
</properties>
Have a look under "Run -> Run Configurations..." in Eclipse. You should delete the new one which you created by mistake, you should still have the existing one.
I suspect it has created a new run configuration for the "Run as Maven Test" and you are now always starting this one.
If you're using Spring Boot and the above suggestions don't work, you might want to look at the Eclipse Problems view (available at Window -> Show View -> Problems).
For example, you can get the same error (Error: Could not find or load main class groupId.Application) if one of your jar files is corrupted. Eclipse will complain that it can't find the Applications class, even though the bad jar is the root cause.
The Problems view, however, will identify the bad jar for you.
At any rate, I had to manually go to my local mvn repo (in .m2) and manually delete the corrupted jar, and update it (right click on the project in the Package Explorer), Maven --> Update Project... -> OK (assuming that the correct project is check-marked).
I tried all the above solution, but didn't worked for me.
Finally was able to resolve it with a simple fix.
on STS,
Run Configuration > open your Spring Boot App > Open your configuration,
Follow the steps,
In Spring boot Tab, check your Main class and profile.
Then go to classpath tab, In the bottom you will see two checkboxes,one is "Exclude Test Code"(Check this if you do not want to run test classes) and other, "Use Temporary Jar file to specify classpath" (this is necessary).
Save your configuration and run.
This happened to me after i updated the pom (Added some dependencies).
The following step helped me to avoid this error
right click on the project > maven > update project
Intellij
close Intellij
remove all files related to Intellij (.idea folder and *.iml files)
open the project in Intellij as if it was the first time (using open recent won't work, id needs to be done via file -> open)
Use spring-boot:run command to start spring boot application:
Precondition:
1. Add following property to pom.xml
<property>
<start-class>com.package.name.YourApplicationMainClass</start-class>
</property>
2. Build your project
Then configure maven command with spring-boot:run.
Navigation:
Right Click Project | Run As | Run Configuration... | Add new Maven Configuration with command spring-boot:run
In case if someone is using Gradle for the build then fix will be by adding the following lines in build.gradle file
apply plugin: 'application'
mainClassName = "com.example.demo.DemoApplication"
The solution for me was:
Boot Dashboard, right click on your Instance.
Open Config
Tab Spring Boot
Main Type, there was the path to the application file missing...
I know this is pretty late answer. But it might still help some new learners.
The Following example is only for springboot with NETBEANS.
I had to do the following steps:
Step 1. Follow #Mariuszs answer .
Step 2. Right click on project -> Properties -> RUN.
Make sure the Main Class field is has the correct starter class else Click browse and select from the available classes .
Step 3. Click OK-> OK. Thant is all. Thank you.
I have used spring 1.5.3.RELEASE version and given pom dependencies like
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>1.5.3.RELEASE</version>
</parent>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
</dependencies>
And my main class was
#SpringBootApplication
public class SpringAppStarter {
public static void main(String[] args) {
SpringApplication.run(SpringAppStarter.class, args);
}
}
But still while execution of main class I was getting:
Could not find or load main class ... with my class name.
I could see that class was available in the class path and I was using STS IDE.
I was not getting reason for the issue then I tried manual build through maven with
mvn clean install
Still problem was there then i realize that my project has two libraries
Reference Library
Maven Library
What I did:
I have created another mavenRepo folder and build it again and refresh my project. After that it worked and I saw that Maven Library was deleted from project class path.
Issues was while execution it was getting multiple version so it was not able to find proper class to execute my application.
Other Solution listed in this page also resolves the issue but if you are doing mistake in
Annotating class
pom entry
jar version etc.
Hope this may resolve problem if somebody get this issue
deleting old jars from .m2 and updating maven project should be primary step.
In most of the cases it resolves the issue.The reason for this issue is mostly corrupted old jars
Encountered the same issue and was able to fix it by the following the steps listed below:
File -> Invalidate Cache and Restart
File -> New -> Project from existing source
Select the pom.xml file just (not the whole project directory) to load the project. Project will be setup automatically.
Error:Could not load or find main class
Project:Spring Boot
Tool:STS
Resolve Steps:
Run the project
See in problems tab, it will show the corrupted error
Delete that particular jar(corrupted jar) in .m2 folder
Update project
Run successfully
I was having the same problem just delete .m2 folder folder from your local repositry
Hope it will work.
start-class doesn't work for me, I fixed it by adding build plugins to pom.xml, and executions is necessary.
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
<executions>
<execution>
<goals>
<goal>repackage</goal>
</goals>
</execution>
</executions>
</plugin>
</plugins>
</build>
There are good answers here, but maybe this one will also help somebody.
For me it happened just after i deleted .idea (with IntelliJ), and reimported the project.
then this issue started, i tried to run mvn compile (just via IDE Maven toolbar), once i fixed few compilation errors, issue disappeared
If you came across the
error:could not find or load main class in maven project
do this it worked for me:
Reason for the error: The reason for this error is the jar file or dependency to run a maven project is not installed correctly.
Solution for the error: Go to the project folder (eg: D:\office\OIA-service-app)
in the address bar of computer type command cmd and press enter.
In the command prompt type command mvn clean install make sure you have the internet connection.
If your project packaging type war you could not start. I was using maven assembly plugin with this configuration;
<build>
<plugins>
<plugin>
<artifactId>maven-assembly-plugin</artifactId>
<version>3.0.0</version><!--$NO-MVN-MAN-VER$ -->
<configuration>
<descriptors>
<descriptor>assembly.xml</descriptor>
</descriptors>
<descriptorRefs>
<descriptorRef>jar-with-dependencies</descriptorRef>
</descriptorRefs>
<archive>
<manifest>
<mainClass>com.ttech.VideoUploaderApplication</mainClass>
</manifest>
</archive>
</configuration>
<executions>
<execution>
<id>make-assembly</id> <!-- this is used for inheritance merges -->
<phase>package</phase> <!-- bind to the packaging phase -->
<goals>
<goal>single</goal>
</goals>
</execution>
</executions>
</plugin>
</plugins>
</build>
and my packaging tpe was war i got cannot find main class exception bu i changed packaging to jar it worked;
<groupId>com.ttect</groupId>
<artifactId>VideoUploadListener</artifactId>
<version>1.0.0</version>
<packaging>**jar**</packaging>
In my case the following helped:
Added the following section in pom
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
<configuration>
<executable>true</executable>
</configuration>
</plugin>
</plugins>
Ran it using maven3 and it worked
I also got this error, was not having any clue. I could see the class and jars in Target folder. I later installed Maven 3.5, switched my local repo from C drive to other drive through conf/settings.xml of Maven. It worked perfectly fine after that. I think having local repo in C drive was main issue. Even though repo was having full access.
I was facing the same problem. I have deleted the target folder and run maven install, it worked.
I had similar kind of problem while I was adding spring security dependency to my project ,
then I deleted my target folder and used maven update again .
It's worked for me.
Even I faced the same issue, later I found that it happened because the maven build operation was not happening properly in my environment. Please check it in your case also.
I ran into same error, although i was using gradle build. Delegating IDE build/run actions to Gradle is solved my problem.
Intellij:
Settings -> Build, Execution, Deployment -> Build Tools -> Gradle -> Runner
I got the same error in the "Spring Tool Suite" software.
In my case, I have Java 8 installed and I created a project of Java 11. And when I run the project I got the same error, like " can not find main class ".
Then I created a project in Java 8 and the problem resolved.
(Eclipse) Updating maven project was not working for me. What I had to do was to go in Run configurations, and in "Main" tab, in "Project" field, write the whole package name com.bla.blabla.MyMainClass (instead of just the Main class name).
The error happened because I have several projects with the same name, but in different packages.
if none of above solutions work, try to replace build tag with this inside pom file :
<build>
<pluginManagement>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins></pluginManagement>
</build>
I am new in spring boot and using STS with maven build. I did all the things mentioned above but won't work for me. I noticed two problems in problem window of STS. There was a missing jar file on the path (C:\Users\UserName.m2\repository\com\jayway\jsonpath\json-path\2.2.0). I did following, the way is not strongly suggested but worked for me.
1) I deleted .m2 folder from the path location
2) Restarted STS
3) Right Click on project folder -> maven -> update project -> checked "Force update of snapshots/releases" -> Click Ok.
Maven updated its dependencies and the problem is solved.