Information about which roads are one-ways is stored using access flags for each edge. This depends on the vehicle/encoder. To find out if an edge is a one way you therefore need to use the access encoded value:
EdgeIteratorState edge = queryResult.getClosestEdge();
int nodeA = edge.getBaseNode();
int nodeB = edge.getAdjNode();
boolean edgeCanBeTraveledFromAToB = edge.get(flagEncoder.getAccessEnc());
boolean edgeCanBeTraveledFromBToA = edge.getReverse(flagEncoder.getAccessEnc());