code: public static Pair<InMemoryJarfile, String> loadAndUpgradeCatalogFromJar(byte[] catalogBytes, boolean isXDCR)
          throws IOException
      {
          // Throws IOException on load failure.
          InMemoryJarfile jarfile = loadInMemoryJarFile(catalogBytes);
  
          return loadAndUpgradeCatalogFromJar(jarfile, isXDCR);
      }
docs: Load a catalog from the jar bytes.
  
  @param catalogBytes
  @param isXDCR
  @return Pair containing updated InMemoryJarFile and upgraded version (or null if it wasn't upgraded)
  @throws IOException
  If the catalog cannot be loaded because it's incompatible, or
  if there is no version information in the catalog.