maven compilation error: duplicate classes - maven-2

Question

In my maven2 project I have a directory ${basedir}/autogen that contains some autogenerated source code files produced by wsdl2java.
When running mvn compile I get an compilation error, because of duplicate classes, that lives in ${basedir}/autogen. This is true. But what is the compilation phase doing in ${basedir}/autogen? I have not told maven to add this directory as a source directory.
And there seems to be no way of telling maven to ignore the directory.

Answer 1

I had the same problem when using the maven-processor-plugin and found that the solution was to configure the maven-compiler plugin as follows:
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>2.1</version>
<configuration>
<source>1.6</source>
<target>1.6</target>
<compilerArgument>-proc:none</compilerArgument>
</configuration>
</plugin>
-proc:none means that compilation takes place without annotation processing and therefore no duplicate classes (which are typically generated in the generate-sources phase)
I hope that helps.

Answer 2

I've seen this a few times. In almost all cases, it is due to the generated classes being added to the main src tree then checked into version control.

Answer 3

In my case, it worked when I changed source directory.
New POM looks like,
<build>
<sourceDirectory>src</sourceDirectory>
Pointing just a src folder with sourceDirectory tag.
Earlier it was
<build>
<sourceDirectory>.</sourceDirectory>
Note that earlier it was working in IntellIJ, but not on cmd.
Now it works on both.

Answer 4

I had a similar problem with JPA model generator. It occurred on this dependency:
<dependency>
<groupId>org.eclipse.persistence</groupId>
<artifactId>org.eclipse.persistence.jpa.modelgen</artifactId>
<version>2.1.1</version>
</dependency>
I wrongly added the scope=provided and that resulted in:
[ERROR] Failed to execute goal org.apache.maven.plugins:maven-compiler-plugin:2.3.1:compile (default-compile) on project mocker: Compilation failure: Compilation failure:
[ERROR] \Projects\entity\MockVehicle_.java:[10,7] duplicate class: entity.MockVehicle_

Answer 5

I had the exact same issue. In my case the problem was that I called maven with -f=./pom.xml. I have no idea why this leads to a different result (would be nice if someone can explain) but maybe good to know if someone else has the same issue.

Answer 6

I resolve it by remove generateAsync from my pom.xml the the GWT plugin will look like
<groupId>org.codehaus.mojo</groupId>
<artifactId>gwt-maven-plugin</artifactId>
<version>${gwtVersion}</version>
<executions>
<execution>
<goals>
<goal>compile</goal>
<goal>test</goal>
<!-- <goal>i18n</goal> -->
</goals>
</execution>
</executions>

Answer 7

Its hard to change default maven behaviour, i think its better to go with it - you could generate those files with maven wsdl2java-maven-plugin

Answer 8

I my case helped this:
<!-- https://mvnrepository.com/artifact/javax.annotation/javax.annotation-api -->
<dependency>
<groupId>javax.annotation</groupId>
<artifactId>javax.annotation-api</artifactId>
<version>1.3.2</version>
</dependency>

Answer 9

All answers here where not helpful. This may be the correct answer:
Another StackOverflow user wrote:
I have found an JetBrains Team member comment stating that:
IDEA automatically excludes the build 'target' folder, providing that
there are no generated sources under it, otherwise it excludes all
sub-folders but the generated.
Avro by standard in a generated-sources folder. This folder it not ignored by maven ans the generated classes in there will count as duplicate.
Maven will only igonre the target folder by default.
To fix add this line in the pom.xml:
<sourceDirectory>${project.basedir}/src/main/target/resources/avro</sourceDirectory>
Context:
<groupId>org.apache.avro</groupId>
<artifactId>avro-maven-plugin</artifactId>
<version>${avro.version}</version>
<executions>
<execution>
<phase>generate-sources</phase>
<goals>
<goal>schema</goal>
<goal>protocol</goal>
<goal>idl-protocol</goal>
</goals>
<configuration>
<sourceDirectory>${project.basedir}/src/main/target/resources/avro</sourceDirectory>
<stringType>String</stringType>
<createSetters>false</createSetters>
<outputDirectory>${project.basedir}/target/</outputDirectory><enableDecimalLogicalType>true</enableDecimalLogicalType>
<fieldVisibility>private</fieldVisibility>
</configuration>
</execution>
</executions>
This will put the generated-resources folder under the target folder.

Answer 10

I resolve the same issue
cleaning maven project :-mvn clean
delete com folder from src then compile
copy com from generated to src->main-->java
again compile
Hope this Help..