CODEWITHSUNDEEP
javalinuxmaventomcat
parsecer
parsecer

Reputation: 5176

Maven: java.lang.NoClassDefFoundErrorexception, but jars are downloaded in .m2

I have a tomcat project: tomcat/webapps/Project. That project makes use of org.json library, the dependency is written in pom.xml file:

<dependency>
    <groupId>org.json</groupId>
    <artifactId>json</artifactId>
    <version>20180813</version>
</dependency>

I have installed maven on my server and run this command, while in the Project directory: mvn install

Then I checked /root/.m2/repository/org/json/20180813 folder and the file json-20180813.jar is there!

However when I restart my server: shutdown.sh and try to make use of my app, the error is still there:

javax.servlet.ServletException: java.lang.NoClassDefFoundError: org/json/JSONObject

Why does this happen and how to fix it?

EDIT: People pointed out the copying of the jar to tomcat/lib directory. I did it and it worked. However, I would also be interested in a more permanent solution, so that I wouldn't be forced to do this again with other jars in the future.

Upvotes: 0

Views: 153

Answers (2)

pirho
pirho

Reputation: 12245

Command mvn install will compile and install your project library to your local repository. In addition it will download and copy any dependencies there also, under that .m2/repository directory. See this question for more detailed explanation about mvn install.

However it has nothing to do with Tomcat or deploying applications to a Tomcat instance. It will not make any libraries available for Tomcat directly.

To make Tomcat use any library there are at least these two options:

  1. You can add them as a dependency in war packaged project. So, you might have something wrong in your pom.xml if you already deploy a WAR and still the library does not seem to be found by Tomcat.

  2. As suggested in other answer you can manually copy the dependencies to the tomcat/lib directory and make the dependency in POM <scope>provided</scope> to prevent those to be packaged to the WAR.

The latter option might be sensible if you do not want to deploy monolithic - say 100MB - war every 5 minutes when developing especialy if doing it over network.

Upvotes: 1

Jonathan Gagne
Jonathan Gagne

Reputation: 4389

If you put your .jar file into your tomcat folder lib, it will work like a charm!

Upvotes: 1

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