Fail to handle transaction on java-rest-binding of Neo4j

I use Java REST binding of Neo4j on my project, but I face a problem on handling transactions.

When the name is Error, it can success insert node into DB..., event if I take off Transaction control, it still works.

final RestAPI api = new RestAPIFacade("http://localhost:7474/db/data");
final RestCypherQueryEngine engine = new RestCypherQueryEngine(api);

Transaction tx = api.beginTx();
try {
    String name = "Error";
    Map<String, Object> subMap = new HashMap<String, Object>();
    subMap.put("name", name);
    subMap.put("age", 17);
    Node node = api.createNode(subMap);
    Label label = DynamicLabel.label("Student");
    node.addLabel(label);

    if("Error".equals(name)) {
        tx.failure();
    }
    else {
        tx.success();
    }
} finally {
    tx.finish();
}

Copyright License：
Author:「LoveTW」,Reproduced under the CC 4.0 BY-SA copyright license with link to original source & disclaimer.
Link to：https://stackoverflow.com/questions/23648082/fail-to-handle-transaction-on-java-rest-binding-of-neo4j