code: public static final ZooSession open(String dbName) {
          if (!ZooHelper.dbExists(dbName)) {
              // create database
              // By default, all database files will be created in %USER_HOME%/zoodb
              ZooHelper.createDb(dbName);
          }
  		return new ZooSession(dbName);
  	}
docs: Opens the database at the given location.
  The database is created if it does not exist.
  By default databases are created in %USER_HOME%/zoodb.
  
  @param dbName The database name or path
  @return ZooRollingSession object