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NoClassDefFoundError after converting a simple java project to a maven project in eclipse

I have a class that I encoded in a standard java project in eclipse on OSX (Java 1.6). A class uses classes and interfaces from another library.
I select a class and then execute as> a Java application and everything works fine.

After that, I try to start the project as a Maven project, and everything starts to get a little upset. I will summarize all the steps here, hoping that someone will tell me what I am doing wrong: - From a standard Java project, I right-clicked and made the setting> Convert to Maven project and clicked Finnish. All is good so far.

  • Then create a path> Configure Build Path> and add the folder containing my project. Still good

  • Then I delete all @Override annotations, since I read SO somewhere that Maven uses JDK 1.5 instead of 1.6. Be that as it may, I delete them, and my red flags go away. At the moment, my class looks exactly the same as in the original java project (except for the deleted @override)

  • Then I make Maven> clean. I get success in building

  • THEN Maven> Install. I get build success

  • Then I select my class and run as> a Java application, and I get this ugly search trace:

    Exception in thread "main" java.lang.NoClassDefFoundError: LMAXTrading / algos / HeartbeatClient Raised: java.lang.ClassNotFoundException: LMAXTrading.algos.HeartbeatClient at java.net.URLClassLoader $ 1.run2java.larclass .AccessController.doPrivileged (native method) on java.net.URLClassLoader.findClass (URLClassLoader.java:190) in java.lang.ClassLoader.loadClass (ClassLoader.java:306) at sun.misc.Launcher $ AppClassLoader.loadClass (Launcher .java: 301) in java.lang.ClassLoader.loadClass (ClassLoader.java:247)

I don’t know where to go from here. You can imagine that I went through many trials and errors and searched in SO and elsewhere to find a way to make this work. But I just can’t understand what’s wrong. Therefore, if anyone has an idea, I am so ready to listen.

I am pasting below my catalog layout from the Navigator view as well as from the package explorer view

layout navigator view

enter image description here

And here is the POM.xml where I added the JRE configuration

<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/xsd/maven-4.0.0.xsd"> <modelVersion>4.0.0</modelVersion> <groupId>someproject</groupId> <artifactId>someproject</artifactId> <version>1.0-SNAPSHOT</version> <build> <plugins> <plugin> <groupId>org.apache.maven.plugins</groupId> <artifactId>maven-compiler-plugin</artifactId> <version>2.3.2</version> <configuration> <source>1.6</source> <target>1.6</target> </configuration> </plugin> </plugins> </build> </project>
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The project directory structure does not match the default Maven directory structure. Maven expects the source to be in the src/main/java directory in the root folder (the folder containing pom.xml ). The source here is in the src folder, hence the error No sources to compile .

You can either move the sources to use the default directory structure of Maven, or modify pom.xml to explicitly specify your source directory by adding the following to the build pom section:

 <sourceDirectory>${basedir}/src</sourceDirectory>

More information on standard Maven layouts can be found here .

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Source: https://habr.com/ru/post/1485720/

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