Error building micro services app

https://spring.io/blog/2015/07/14/microservices-with-spring

Below shows the error. Solution is adding below snipet , "start-class" for the POM. Try building with "mvn clean package"

Solution :

<properties>
<start-class>io.pivotal.microservices.services.Main</start-class>
</properties>


Then run the jar with specifying which main method needs to be choose.

eg :
java -jar microservices-demo-2.0.0.RELEASE.jar account
java -jar microservices-demo-2.0.0.RELEASE.jar account
java -jar microservices-demo-2.0.0.RELEASE.jar account


------ Error --------------------------------

[INFO] Finished at: 2018-08-10T16:41:48+05:30
[INFO] ------------------------------------------------------------------------
[ERROR] Failed to execute goal org.springframework.boot:spring-boot-maven-plugin:2.0.1.RELEASE:repackage (default) on project EurekaServer1: Execution default of goal org.springframework.boot:spring-boot-maven-plugin:2.0.1.RELEASE:repackage failed: Unable to find a single main class from the following candidates
[io.pivotal.microservices.services.registration.RegistrationServer, io.pivotal.microservices.services.web.WebServer] ->
[Help 1]org.apache.maven.lifecycle.LifecycleExecutionException: Failed to execute goal org.springframework.boot:spring-boot-maven-plugin:2.0.1.RELEASE:repackage (default) on project EurekaServer1: Execution default of goal org.springframework.boot:spring-boot-maven-plugin:2.0.1.RELEASE:repackage failed: Unable to find a single main class from the following candidates
[io.pivotal.microservices.services.registration.RegistrationServer, io.pivotal.microservices.services.web.WebServer] at org.apache.maven.lifecycle.internal.MojoExecutor.execute (MojoExecutor.java:213) at org.apache.maven.lifecycle.internal.MojoExecutor.execute (MojoExecutor.java:154) at org.apache.maven.lifecycle.internal.MojoExecutor.execute (MojoExecutor.java:146) 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:954) at org.apache.maven.cli.MavenCli.doMain (MavenCli.java:288) at org.apache.maven.cli.MavenCli.main (MavenCli.java:192) 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:497) at org.codehaus.plexus.classworlds.launcher.Launcher.launchEnhanced (Launcher.java:289) at org.codehaus.plexus.classworlds.launcher.Launcher.launch (Launcher.java:229) at org.codehaus.plexus.classworlds.launcher.Launcher.mainWithExitCode (Launcher.java:415) at org.codehaus.plexus.classworlds.launcher.Launcher.main (Launcher.java:356)Caused by: org.apache.maven.plugin.PluginExecutionException: Execution default of goal org.springframework.boot:spring-boot-maven-plugin:2.0.1.RELEASE:repackage failed: Unable to find a single main class from the following candidates
[io.pivotal.microservices.services.registration.RegistrationServer, io.pivotal.microservices.services.web.WebServer] at org.apache.maven.plugin.DefaultBuildPluginManager.executeMojo (DefaultBuildPluginManager.java:148) at org.apache.maven.lifecycle.internal.MojoExecutor.execute (MojoExecutor.java:208) at org.apache.maven.lifecycle.internal.MojoExecutor.execute (MojoExecutor.java:154) at org.apache.maven.lifecycle.internal.MojoExecutor.execute (MojoExecutor.java:146) 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:954) at org.apache.maven.cli.MavenCli.doMain (MavenCli.java:288) at org.apache.maven.cli.MavenCli.main (MavenCli.java:192) 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:497) at org.codehaus.plexus.classworlds.launcher.Launcher.launchEnhanced (Launcher.java:289) at org.codehaus.plexus.classworlds.launcher.Launcher.launch (Launcher.java:229) at org.codehaus.plexus.classworlds.launcher.Launcher.mainWithExitCode (Launcher.java:415) at org.codehaus.plexus.classworlds.launcher.Launcher.main (Launcher.java:356)Caused by: java.lang.IllegalStateException: Unable to find a single main class from the following candidates
[io.pivotal.microservices.services.registration.RegistrationServer, io.pivotal.microservices.services.web.WebServer] at org.springframework.boot.loader.tools.MainClassFinder$SingleMainClassCallback.getMainClassName (MainClassFinder.java:451) at org.springframework.boot.loader.tools.MainClassFinder$SingleMainClassCallback.access$100 (MainClassFinder.java:421) at org.springframework.boot.loader.tools.MainClassFinder.findSingleMainClass (MainClassFinder.java:205) at org.springframework.boot.loader.tools.Repackager.findMainMethod (Repackager.java:333) at org.springframework.boot.loader.tools.Repackager.findMainMethodWithTimeoutWarning (Repackager.java:322) at org.springframework.boot.loader.tools.Repackager.buildManifest (Repackager.java:293) at org.springframework.boot.loader.tools.Repackager.repackage (Repackager.java:238) at org.springframework.boot.loader.tools.Repackager.repackage (Repackager.java:195) at org.springframework.boot.maven.RepackageMojo.repackage (RepackageMojo.java:221) at org.springframework.boot.maven.RepackageMojo.execute (RepackageMojo.java:208) at org.apache.maven.plugin.DefaultBuildPluginManager.executeMojo (DefaultBuildPluginManager.java:137) at org.apache.maven.lifecycle.internal.MojoExecutor.execute (MojoExecutor.java:208) at org.apache.maven.lifecycle.internal.MojoExecutor.execute (MojoExecutor.java:154) at org.apache.maven.lifecycle.internal.MojoExecutor.execute (MojoExecutor.java:146) 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:954) at org.apache.maven.cli.MavenCli.doMain (MavenCli.java:288) at org.apache.maven.cli.MavenCli.main (MavenCli.java:192) 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:497) at org.codehaus.plexus.classworlds.launcher.Launcher.launchEnhanced (Launcher.java:289) at org.codehaus.plexus.classworlds.launcher.Launcher.launch (Launcher.java:229) at org.codehaus.plexus.classworlds.launcher.Launcher.mainWithExitCode (Launcher.java:415) at org.codehaus.plexus.classworlds.launcher.Launcher.main (Launcher.java:356)
[ERROR]
[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/PluginExecutionExceptionC:\BackUp_2016_07_14\NonFilter\Projects\EAG\code\Spring\SpringBoot\EurekaServer1>




Now we have another error running jar with argument specifying the service.

Reason: we have not added the Main.java  class we have specified inside the POM. when we build the jar, earlier we had an issue with too many main methods. As we need to get rid of that we specifies a class which needs to be taken as a main class inside POM.
It build the jar without checking the existence of the class.

Solution :
So we create the Main.java class in the specified package.

Error is below when class in not present.

------------------------
Exception in thread "main" java.lang.ClassNotFoundException: io.pivotal.microservices.services.Main
        at java.net.URLClassLoader.findClass(Unknown Source)
        at java.lang.ClassLoader.loadClass(Unknown Source)
        at org.springframework.boot.loader.LaunchedURLClassLoader.loadClass(LaunchedURLClassLoader.java:93)
        at java.lang.ClassLoader.loadClass(Unknown Source)
        at org.springframework.boot.loader.MainMethodRunner.run(MainMethodRunner.java:46)
        at org.springframework.boot.loader.Launcher.launch(Launcher.java:87)
        at org.springframework.boot.loader.Launcher.launch(Launcher.java:50)
        at org.springframework.boot.loader.JarLauncher.main(JarLauncher.java:51)