public static ExecutionSystem newExecutionSystem(URI uri,Map<String,?> env) throws IOException {
  return newExecutionSystem(uri,env,null);
}

public static ExecutionSystem newExecutionSystem ( URI uri , Map < String , ? > env ) throws IOException { return newExecutionSystem ( uri , env , null ) ; }
creates a new execution system for the specified uri . the number of execution systems with a given uri that may open at the same time is implementation dependent .
