Plugin fails with "java.lang.ClassNotFoundException: List" on spring boot project

[mayurvpatil]

Used this plugin in existing spring boot project,
I used same plugin with non spring boot project and it's working perfect.

Plugin used in POM is as follows,

<plugin>
	<groupId>com.github.kongchen</groupId>
	<artifactId>swagger-maven-plugin</artifactId>
	<version>3.1.7</version>
	<configuration>
		<apiSources>
			<apiSource>
				<springmvc>true</springmvc>
				 <basePath>/</basePath>
				<locations>com.project</locations>
				<schemes>http,https</schemes>
				<!-- <basePath>/api</basePath> -->
				<info>
					<title>MyService</title>
					<version>${project.version}</version>
				</info>
				<swaggerDirectory>swagger</swaggerDirectory>
			</apiSource>
		</apiSources>
	</configuration>
</plugin>

Error as follows,

java.lang.ClassNotFoundException: List
	at org.codehaus.plexus.classworlds.strategy.SelfFirstStrategy.loadClass(SelfFirstStrategy.java:50)
	at org.codehaus.plexus.classworlds.realm.ClassRealm.unsynchronizedLoadClass(ClassRealm.java:271)
	at org.codehaus.plexus.classworlds.realm.ClassRealm.loadClass(ClassRealm.java:247)
	at org.codehaus.plexus.classworlds.realm.ClassRealm.loadClass(ClassRealm.java:239)
	at io.swagger.util.ReflectionUtils.loadClassByName(ReflectionUtils.java:49)
	at io.swagger.jackson.ModelResolver.getInnerType(ModelResolver.java:841)
	at io.swagger.jackson.ModelResolver.resolve(ModelResolver.java:441)
	at com.github.kongchen.swagger.docgen.reader.ModelModifier.resolve(ModelModifier.java:96)
	at io.swagger.jackson.ModelResolver.resolve(ModelResolver.java:185)
	at com.github.kongchen.swagger.docgen.reader.ModelModifier.resolve(ModelModifier.java:90)
	at io.swagger.converter.ModelConverterContextImpl.resolve(ModelConverterContextImpl.java:100)
	at io.swagger.jackson.ModelResolver.resolve(ModelResolver.java:236)
	at com.github.kongchen.swagger.docgen.reader.ModelModifier.resolve(ModelModifier.java:96)
	at io.swagger.jackson.ModelResolver.resolve(ModelResolver.java:185)
	at com.github.kongchen.swagger.docgen.reader.ModelModifier.resolve(ModelModifier.java:90)
	at io.swagger.converter.ModelConverterContextImpl.resolve(ModelConverterContextImpl.java:100)
	at io.swagger.jackson.ModelResolver.resolveProperty(ModelResolver.java:161)
	at io.swagger.jackson.ModelResolver.resolveProperty(ModelResolver.java:112)
	at com.github.kongchen.swagger.docgen.reader.ModelModifier.resolveProperty(ModelModifier.java:76)
	at io.swagger.converter.ModelConverterContextImpl.resolveProperty(ModelConverterContextImpl.java:80)
	at io.swagger.converter.ModelConverters.readAsProperty(ModelConverters.java:58)
	at com.github.kongchen.swagger.docgen.reader.AbstractReader.isPrimitive(AbstractReader.java:297)
	at com.github.kongchen.swagger.docgen.reader.SpringMvcApiReader.parseMethod(SpringMvcApiReader.java:236)
	at com.github.kongchen.swagger.docgen.reader.SpringMvcApiReader.read(SpringMvcApiReader.java:127)
	at com.github.kongchen.swagger.docgen.reader.SpringMvcApiReader.read(SpringMvcApiReader.java:70)
	at com.github.kongchen.swagger.docgen.AbstractDocumentSource.loadDocuments(AbstractDocumentSource.java:118)
	at com.github.kongchen.swagger.docgen.mavenplugin.ApiDocumentMojo.execute(ApiDocumentMojo.java:96)
	at org.apache.maven.plugin.DefaultBuildPluginManager.executeMojo(DefaultBuildPluginManager.java:137)
	at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:210)
	at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:156)
	at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:148)
	at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject(LifecycleModuleBuilder.java:117)
	at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject(LifecycleModuleBuilder.java:81)
	at org.apache.maven.lifecycle.internal.builder.singlethreaded.SingleThreadedBuilder.build(SingleThreadedBuilder.java:56)
	at org.apache.maven.lifecycle.internal.LifecycleStarter.execute(LifecycleStarter.java:128)
	at org.apache.maven.DefaultMaven.doExecute(DefaultMaven.java:305)
	at org.apache.maven.DefaultMaven.doExecute(DefaultMaven.java:192)
	at org.apache.maven.DefaultMaven.execute(DefaultMaven.java:105)
	at org.apache.maven.cli.MavenCli.execute(MavenCli.java:957)
	at org.apache.maven.cli.MavenCli.doMain(MavenCli.java:289)
	at org.apache.maven.cli.MavenCli.main(MavenCli.java:193)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:498)
	at org.codehaus.plexus.classworlds.launcher.Launcher.launchEnhanced(Launcher.java:282)
	at org.codehaus.plexus.classworlds.launcher.Launcher.launch(Launcher.java:225)
	at org.codehaus.plexus.classworlds.launcher.Launcher.mainWithExitCode(Launcher.java:406)
	at org.codehaus.plexus.classworlds.launcher.Launcher.main(Launcher.java:347)
[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Total time:  10.081 s
[INFO] Finished at: 2020-12-02T15:53:51+05:30
[INFO] ------------------------------------------------------------------------
[ERROR] Failed to execute goal com.github.kongchen:swagger-maven-plugin:3.1.6:generate (default-cli) on project test-service: Unrecognized Type: [null] -> [Help 1]
[ERROR] 
[ERROR] To see the full stack trace of the errors, re-run Maven with the -e switch.
[ERROR] Re-run Maven using the -X switch to enable full debug logging.
[ERROR] 
[ERROR] For more information about the errors and possible solutions, please read the following articles:
[ERROR] [Help 1] http://cwiki.apache.org/confluence/display/MAVEN/MojoExecutionException

[junaid88]

I am facing the same problem Any update?