code: public void excludeClass(String... classNames) {
          if (classNames == null) {
              excludeClassNames = null;
          } else {
              for (String className : classNames) {
                  if (!isExcludePackage(className)) {
                      if (excludeClassNames == null) {
                          excludeClassNames = new HashSet<>();
                      }
                      excludeClassNames.add(className);
                  }
              }
          }
      }
docs: Adds classes that this ClassLoader should not handle.
  Any class whose fully-qualified name starts with the name registered here will be handled
  by the parent ClassLoader in the usual fashion.
  
  @param classNames class names that we be compared against fully qualified class names to exclude