code: private void createSPIFile(String moduleName) {
          try {
              final FileObject fo = this.processingEnv.getFiler().createResource(StandardLocation.CLASS_OUTPUT, "", MODULE_STARTER_SPI_PATH);
              this.processingEnv.getMessager().printMessage(Diagnostic.Kind.NOTE, "creating spi file: " + fo.toUri());
  
              final Writer writer = fo.openWriter();
              writer.write(moduleName);
              writer.close();
          } catch (final IOException e) {
              e.printStackTrace();
              throw new RuntimeException(e);
          }
  
      }
docs: Creates SPI file to expose the module stater
  
  @param moduleName the name of the module