Example:
org.jvnet.jaxb2.maven2
you should change that to define the plugin only once and do twice execution areas...like the following...and the generateDirectory should be set (based on the docs)..
<plugin>
<groupId>org.jvnet.jaxb2.maven2</groupId>
<artifactId>maven-jaxb2-plugin</artifactId>
<version>0.7.1</version>
<executions>
<execution>
<id>firstrun</id>
<goals>
<goal>generate</goal>
</goals>
<configuration>
<generateDirectory>target/gen1</generateDirectory>
<schemaDirectory>src/main/resources/dir1</schemaDirectory>
<schemaIncludes>
<include>schema1.xsd</include>
</schemaIncludes>
<generatePackage>schema1.package</generatePackage>
</configuration>
</execution>
<execution>
<id>secondrun</id>
<goals>
<goal>generate</goal>
</goals>
<configuration>
<generateDirectory>target/gen2</generateDirectory>
<schemaDirectory>src/main/resources/dir2</schemaDirectory>
<schemaIncludes>
<include>schema2.xsd</include>
</schemaIncludes>
<generatePackage>schema2.package</generatePackage>
</configuration>
</execution>
</executions>
</plugin>
It seemed to me that you are fighting against single artifact rule of maven...may be you should think about this.
The following works for me, after much trial
<plugin>
<groupId>org.codehaus.mojo</groupId>
<artifactId>jaxb2-maven-plugin</artifactId>
<version>2.1</version>
<executions>
<execution>
<id>xjc1</id>
<goals>
<goal>xjc</goal>
</goals>
<configuration>
<packageName>com.mycompany.clientSummary</packageName>
<sourceType>wsdl</sourceType>
<sources>
<source>src/main/resources/wsdl/GetClientSummary.wsdl</source>
</sources>
<outputDirectory>target/generated-sources/xjb</outputDirectory>
<clearOutputDir>false</clearOutputDir>
</configuration>
</execution>
<execution>
<id>xjc2</id>
<goals>
<goal>xjc</goal>
</goals>
<configuration>
<packageName>com.mycompany.wsclient.employerProfile</packageName>
<sourceType>wsdl</sourceType>
<sources>
<source>src/main/resources/wsdl/GetEmployerProfile.wsdl</source>
</sources>
<outputDirectory>target/generated-sources/xjb</outputDirectory>
<clearOutputDir>false</clearOutputDir>
</configuration>
</execution>
<execution>
<id>xjc3</id>
<goals>
<goal>xjc</goal>
</goals>
<configuration>
<packageName>com.mycompany.wsclient.producersLicenseData</packageName>
<sourceType>wsdl</sourceType>
<sources>
<source>src/main/resources/wsdl/GetProducersLicenseData.wsdl</source>
</sources>
<outputDirectory>target/generated-sources/xjb</outputDirectory>
<clearOutputDir>false</clearOutputDir>
</configuration>
</execution>
</executions>
</plugin>
There is another, a clear one (IMO) solution to this There is a parameter called "staleFile" that uses as a flag to not generate stuff again. Simply alter it in each execution.