maven compilation error: duplicate classes

Question

In my maven2 project I have a directory ${basedir}/autogen that contains some autogenerated source code files produced by wsdl2java.

When r

Answer 1

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 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

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 4

I resolve the same issue

1. cleaning maven project :-mvn clean
2. delete com folder from src then compile
3. copy com from generated to src->main-->java
4. again compile

Hope this Help..

Answer 5

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 6

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.