code: public static String uniqueEnvironment(String prefix, String suffix, 
              File directory) throws IOException {
          File tmpDir = 
                  UNIQUE_DIRECTORY_CREATOR.create(prefix, suffix, directory);
          String randomFilename = UUID.randomUUID().toString();
          File envNameAsFile = new File(tmpDir, randomFilename);
          return envNameAsFile.getAbsolutePath();
      }
docs: Creates a unique directory for housing a BDB environment, and returns
  its name.
  
  @param prefix a prefix for the temporary directory's name. Cannot be
  <code>null</code>.
  @param suffix a suffix for the temporary directory's name.
  @return the environment name to use.
  @param directory the parent directory to use.
  
  @throws IOException if an error occurred in creating the temporary
  directory.