code: @Override
      protected boolean shouldExecutionBeSkipped() {
  
          boolean toReturn = false;
  
          if ("pom".equalsIgnoreCase(getProject().getPackaging())) {
              warnAboutIncorrectPluginConfiguration("packaging", "POM-packaged projects should not generate XSDs.");
              toReturn = true;
          }
  
          if (getSources().isEmpty()) {
              warnAboutIncorrectPluginConfiguration("sources", "At least one Java Source file has to be included.");
              toReturn = true;
          }
  
          // All done.
          return toReturn;
      }
docs: <p>XSD schema files are not generated from POM projects or if no includes have been supplied.</p>
  {@inheritDoc}