Serializable import/implements to jaxrs-cxf spec models when serializableModel is set doesn't work

Description

Serializable import/implements to jaxrs-cxf spec models when serializableModel is set doesn't work

Swagger-codegen version

2.3.1

Swagger declaration file content or url

Command line used for generation

<plugin>
	<groupId>io.swagger</groupId>
	<artifactId>swagger-codegen-maven-plugin</artifactId>
	<version>2.3.1</version>
	<executions>
		<execution>
			<phase>generate-sources</phase>
			<goals>
				<goal>generate</goal>
			</goals>
			<configuration>
				<output>${project.build.directory}/generated-sources</output>
				<inputSpec>${project.basedir}/src/main/resources/spec.yaml</inputSpec>
				<language>jaxrs-cxf</language>
				<generateApis>true</generateApis>
				<addCompileSourceRoot>false</addCompileSourceRoot>
				<generateApiTests>true</generateApiTests>
				<generateModels>true</generateModels>
				<modelPackage>com.company.api.datatypes</modelPackage>
				<apiPackage>com.company.api</apiPackage>
				<invokerPackage>com.company.api.impl</invokerPackage>
				<groupId>com.company</groupId>
				<artifactId>com.company.api</artifactId>
				<artifactVersion>1.0.0</artifactVersion>
				<verbose>true</verbose>
				<configOptions>
					<serializableModel>true</serializableModel>
				</configOptions>
			</configuration>
		</execution>
	</executions>
</plugin>

Doing the same while changing jaxrs-cxf to java produce classes that implements serializable

Start with the jaxrs-cxf generator configuration and templates, using the provided Maven setup with serializableModel enabled. Compare its generated models with the java generator's output, then verify that jaxrs-cxf models import and implement Serializable when the option is set.