code: public ClassInfo getClassInfo(final String className) {
          if (closed.get()) {
              throw new IllegalArgumentException("Cannot use a ScanResult after it has been closed");
          }
          if (!scanSpec.enableClassInfo) {
              throw new IllegalArgumentException("Please call ClassGraph#enableClassInfo() before #scan()");
          }
          return classNameToClassInfo.get(className);
      }
docs: Get the {@link ClassInfo} object for the named class, or null if no class of the requested name was found in
  a whitelisted/non-blacklisted package during the scan.
  
  @param className
  The class name.
  @return The {@link ClassInfo} object for the named class, or null if the class was not found.