I have a Jersey application that's currently using Swagger 1.6
Below are the important segments from the pom file of the project
<dependency>
<groupId>io.swagger</groupId>
<artifactId>swagger-annotations</artifactId>
<version>1.6.1</version>
</dependency>
<dependency>
<groupId>io.swagger</groupId>
<artifactId>swagger-jersey-jaxrs</artifactId>
<version>1.6.1</version>
</dependency>
<build>
<plugins>
<plugin>
<groupId>com.github.kongchen</groupId>
<artifactId>swagger-maven-plugin</artifactId>
<version>3.1.7</version>
<configuration>
<apiSources>
<apiSource>
<springmvc>false</springmvc>
<locations>
<location>com.example.resource</location>
</locations>
<schemes>
<scheme>http</scheme>
<scheme>https</scheme>
</schemes>
<host>www.example.com:8080</host>
<basePath>/api-docs</basePath>
<info>
<title>Swagger Maven Plugin Sample</title>
<version>v1</version>
<description>Sample for Swagger Maven Plaugin</description>
<termsOfService>
http://www.example.com/tos
</termsOfService>
<contact>
<email>abc@test.com</email>
<name>Example App</name>
<url>http://test.com</url>
</contact>
<license>
<url>http://www.apache.org/licenses/LICENSE-2.0.html</url>
<name>Apache 2.0</name>
</license>
</info>
<templatePath>${basedir}/templates/strapdown.html.hbs</templatePath>
<outputPath>${basedir}/generated/document.html</outputPath>
<swaggerDirectory>${basedir}/generated/swagger-ui</swaggerDirectory>
</apiSource>
</apiSources>
</configuration>
<executions>
<execution>
<phase>compile</phase>
<goals>
<goal>generate</goal>
</goals>
</execution>
</executions>
<dependencies>
<dependency>
<groupId>io.swagger</groupId>
<artifactId>swagger-hibernate-validations</artifactId>
<version>1.5.19</version>
</dependency>
</dependencies>
</plugin>
</plugins>
</build>
This works fine and the static documentation generated during build process is proper. When Swagger is updated to use Swagger v3 as below
<dependency>
<groupId>io.swagger.core.v3</groupId>
<artifactId>swagger-annotations</artifactId>
<version>2.1.4</version>
</dependency>
<dependency>
<groupId>io.swagger.core.v3</groupId>
<artifactId>swagger-jaxrs2</artifactId>
<version>2.1.4</version>
</dependency>
the documentation is generated but the descriptions are missing (seems like the v3 annotations were not considered) although versions of 3.x of the plugin support the Swagger 3 annotations. To solve the problem, the version of the plugin was changed to 3.1.8 but then I end up with the below error during mvn clean install.
[ERROR] Failed to execute goal com.github.kongchen:swagger-maven-plugin:3.1.8:generate (default) on project example-rest: null: MojoExecutionException: NullPointerException -> [Help 1]
org.apache.maven.lifecycle.LifecycleExecutionException: Failed to execute goal com.github.kongchen:swagger-maven-plugin:3.1.8:generate (default) on project example-rest: null
at org.apache.maven.lifecycle.internal.MojoExecutor.execute (MojoExecutor.java:215)
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)
Caused by: org.apache.maven.plugin.MojoExecutionException
at com.github.kongchen.swagger.docgen.mavenplugin.ApiDocumentMojo.execute (ApiDocumentMojo.java:152)
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)
Caused by: java.lang.NullPointerException
at com.github.kongchen.swagger.docgen.AbstractDocumentSource.toSwaggerDocuments (AbstractDocumentSource.java:203)
at com.github.kongchen.swagger.docgen.mavenplugin.ApiDocumentMojo.execute (ApiDocumentMojo.java:130)
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)
[ERROR]
[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
What can be the reason for Null pointer exception, or what can be the reason for the Swagger 3 annotations being not considered although it's supported?
Replacing the plugin with the one below works
<plugin>
<groupId>io.openapitools.swagger</groupId>
<artifactId>swagger-maven-plugin</artifactId>
<version>2.1.4</version>
<executions>
<execution>
<goals>
<goal>generate</goal>
</goals>
</execution>
</executions>
<configuration>
<swaggerConfig>
<servers>
<server>
<url>https://www.example.com:8080/cas/api</url>
</server>
</servers>
<info>
<title>${project.name}</title>
<description>${project.description}</description>
<version>${project.version}</version>
</info>
</swaggerConfig>
<resourcePackages>com.cerner.careaware.rest.personnel</resourcePackages>
<useResourcePackagesChildren>true</useResourcePackagesChildren>
<outputDirectory>${basedir}/generated/openapi/</outputDirectory>
<outputFilename>openApiSpec</outputFilename>
<outputFormats>JSON,YAML</outputFormats>
<prettyPrint>true</prettyPrint>
<attachSwaggerArtifact>true</attachSwaggerArtifact>
</configuration>
</plugin>