code: public void addModuleLayer(final Object moduleLayer) {
          if (!isModuleLayer(moduleLayer)) {
              throw new IllegalArgumentException("moduleLayer must be of type java.lang.ModuleLayer");
          }
          if (this.addedModuleLayers == null) {
              this.addedModuleLayers = new ArrayList<>();
          }
          this.addedModuleLayers.add(moduleLayer);
      }
docs: Add a ModuleLayer to the list of ModuleLayers to scan. Use this method if you define your own ModuleLayer,
  but the scanning code is not running within that custom ModuleLayer.
  
  <p>
  This call is ignored if it is called before {@link #overrideModuleLayers(Object...)}.
  
  @param moduleLayer
  The additional ModuleLayer to scan. (The parameter is of type {@link Object} for backwards
  compatibility with JDK 7 and JDK 8, but the argument should be of type ModuleLayer.)