code: public DescriptorMergeStrategy getStrategy(String descriptorUrl, Document descriptorDom) {
          DescriptorMergeStrategy strategy;
  
          if (CollectionUtils.isNotEmpty(resolvers)) {
              for (DescriptorMergeStrategyResolver resolver : resolvers) {
                  strategy = resolver.getStrategy(descriptorUrl, descriptorDom);
                  if (strategy != null) {
                      return strategy;
                  }
              }
          }
  
          return defaultStrategy;
      }
docs: Returns the first non-null strategy returned by a {@link DescriptorMergeStrategyResolver} of the chain.
  If there a no resolvers in the chain, or non of resolvers returns a {@link DescriptorMergeStrategy}, a
  default strategy is returned.
  
  @param descriptorUrl the URL that identifies the descriptor
  @param descriptorDom the XML DOM of the descriptor
  @return the first non-null strategy returned by a {@link DescriptorMergeStrategyResolver} of the chain,
  or a default one if all the resolvers returned null.