Improve error message for empty *.java-File

I have an empty file within my sources dir: "TrpRunner.java". This contains no java source code (everything commented out).
The scp-plugin fails with the following error message:

Unable to load compiled class: com.cedarsoft.deger.ui.TrpRunner -> [Help 1]
org.apache.maven.lifecycle.LifecycleExecutionException: Failed to execute goal org.apache.felix:maven-scr-plugin:1.9.0:scr (generate-scr-scrdescriptor) on project DEGERsoft: Unable to load compiled class: com.cedarsoft.deger.ui.TrpRunner
at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:213)
at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:153)
at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:145)
at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject(LifecycleModuleBuilder.java:84)
at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject(LifecycleModuleBuilder.java:59)
at org.apache.maven.lifecycle.internal.LifecycleStarter.singleThreadedBuild(LifecycleStarter.java:183)
at org.apache.maven.lifecycle.internal.LifecycleStarter.execute(LifecycleStarter.java:161)
at org.apache.maven.DefaultMaven.doExecute(DefaultMaven.java:319)
at org.apache.maven.DefaultMaven.execute(DefaultMaven.java:156)
at org.apache.maven.cli.MavenCli.execute(MavenCli.java:537)
at org.apache.maven.cli.MavenCli.doMain(MavenCli.java:196)
at org.apache.maven.cli.MavenCli.main(MavenCli.java:141)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:601)
at org.codehaus.plexus.classworlds.launcher.Launcher.launchEnhanced(Launcher.java:290)
at org.codehaus.plexus.classworlds.launcher.Launcher.launch(Launcher.java:230)
at org.codehaus.plexus.classworlds.launcher.Launcher.mainWithExitCode(Launcher.java:409)
at org.codehaus.plexus.classworlds.launcher.Launcher.main(Launcher.java:352)
Caused by: org.apache.maven.plugin.MojoFailureException: Unable to load compiled class: com.cedarsoft.deger.ui.TrpRunner
at org.apache.felix.scrplugin.mojo.SCRDescriptorMojo.execute(SCRDescriptorMojo.java:263)
at org.apache.maven.plugin.DefaultBuildPluginManager.executeMojo(DefaultBuildPluginManager.java:101)
at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:209)
... 19 more
Caused by: org.apache.felix.scrplugin.SCRDescriptorFailureException: Unable to load compiled class: com.cedarsoft.deger.ui.TrpRunner
at org.apache.felix.scrplugin.helper.ClassScanner.scanSources(ClassScanner.java:154)
at org.apache.felix.scrplugin.SCRDescriptorGenerator.execute(SCRDescriptorGenerator.java:149)
at org.apache.felix.scrplugin.mojo.SCRDescriptorMojo.execute(SCRDescriptorMojo.java:248)
... 21 more
Caused by: java.lang.ClassNotFoundException: com.cedarsoft.deger.ui.TrpRunner
at java.net.URLClassLoader$1.run(URLClassLoader.java:366)
at java.net.URLClassLoader$1.run(URLClassLoader.java:355)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:354)
at java.lang.ClassLoader.loadClass(ClassLoader.java:423)
at java.lang.ClassLoader.loadClass(ClassLoader.java:356)
at org.apache.felix.scrplugin.helper.ClassScanner.scanSources(ClassScanner.java:141)
... 23 more