public CategoryBuilder() {
   category = new Category();
   category.setName("integrated weapon systems");
   category.setDomain(new DomainBuilder().build());
   category.setChildCategories(null);
   category.setParentCategory(null);
 }
 public CategoryBuilder withParentCategory(Category parentCategory) {
   category.setParentCategory(parentCategory);
   return this;
 }