code: public ZooJdoProperties setZooFailOnEmptyQueries(boolean flag) {
      	DBTracer.logCall(this, flag); 
  		put(ZooConstants.PROPERTY_FAIL_ON_CLOSED_QUERIES, Boolean.toString(flag));
  		return this;
  	}
docs: Property that defines how access to closed Queries and Extent should be handled.
  Queries and Extents are automatically closed at transaction boundaries.
  y default, as specified in JDO 3.1, closed queries and extents behave as if they were
  empty.
  
  ZooDB allows to change this behavior such that access to closed Queries and Extents
  cause an Exception to be thrown. This may be desirable because it can indicate
  erroneous access to invalidated queries and extents, suggesting that they
  were fully traversed, rather than indicating that the result appears only empty because
  it is accessed at the wrong time.
  Default is {@code false}.
  @param flag The flag
  @return this
  @see ZooConstants#PROPERTY_FAIL_ON_CLOSED_QUERIES