code: public static InMemoryJarfile loadInMemoryJarFile(byte[] catalogBytes)
              throws IOException
      {
          assert(catalogBytes != null);
  
          InMemoryJarfile jarfile = new InMemoryJarfile(catalogBytes);
          if (!jarfile.containsKey(CATALOG_FILENAME)) {
              throw new IOException("Database catalog not found - please build your application using the current version of VoltDB.");
          }
  
          return jarfile;
      }
docs: Load an in-memory catalog jar file from jar bytes.
  
  @param catalogBytes
  @param log
  @return The in-memory jar containing the loaded catalog.
  @throws IOException If the catalog cannot be loaded.