Error reading JSON Cypher and Rest API Neo4j

Question

I am trying to execute a Cypher Query over REST API through java using the neo4j-rest-graphdb-2.0.0-M06.jar . from http://m2.neo4j.org/content/repositories/releases/org/neo4j/neo4j-rest-graphdb/2.0.0-M06/neo4j-rest-graphdb-2.0.0-M06.jar .

The java code I use is :

RestAPI graphdb1 = new RestAPIFacade(dbpath);
QueryEngine engine1 = new RestCypherQueryEngine(graphdb1);
String cypherQuery= "match (X)-[:rel1]-(Y) where X:LABEL_X and Y:LABEL_Y return X.id,X.name";       
engine1.query(cypherQuery, Collections.EMPTY_MAP);

I get an exception :

Exception in thread "main" java.lang.RuntimeException: **Error reading as JSON** ''
    at org.neo4j.rest.graphdb.util.JsonHelper.readJson(JsonHelper.java:57)
    at org.neo4j.rest.graphdb.util.JsonHelper.jsonToSingleValue(JsonHelper.java:62)
    at org.neo4j.rest.graphdb.RequestResult.toEntity(RequestResult.java:114)
    at org.neo4j.rest.graphdb.RequestResult.toMap(RequestResult.java:120)
    at org.neo4j.rest.graphdb.ExecutingRestRequest.toMap(ExecutingRestRequest.java:212)
    at org.neo4j.rest.graphdb.ExecutingRestAPI.query(ExecutingRestAPI.java:544)
    at org.neo4j.rest.graphdb.ExecutingRestAPI.query(ExecutingRestAPI.java:564)
    at org.neo4j.rest.graphdb.RestAPIFacade.query(RestAPIFacade.java:234)
    at org.neo4j.rest.graphdb.query.RestCypherQueryEngine.query(RestCypherQueryEngine.java:50)
    at com.unmetric.graph.test.GraphConnectTest.testRestApi(GraphConnectTest.java:39)
    at com.unmetric.graph.test.GraphConnectTest.main(GraphConnectTest.java:26)
**Caused by: java.io.EOFException: No content to map to Object due to end of input**
    at org.codehaus.jackson.map.ObjectMapper._initForReading(ObjectMapper.java:2775)
    at org.codehaus.jackson.map.ObjectMapper._readMapAndClose(ObjectMapper.java:2718)
    at org.codehaus.jackson.map.ObjectMapper.readValue(ObjectMapper.java:1863)
    at org.neo4j.rest.graphdb.util.JsonHelper.readJson(JsonHelper.java:55)
    ... 10 more

In the neo4j web admin interface ? Yes I get results. I saw the code in ExecutingRestApi.class in org.neo4j.rest.graphdb : public Map<?, ?> query(String statement, Map<String, Object> params) { params = (params==null) ? Collections.<String,Object>emptyMap() : params; final RequestResult requestResult = getRestRequest().post("cypher", MapUtil.map("query", statement, "params", params)); return getRestRequest().toMap(requestResult); } Is this the causing the problem, should the method signature be CypherResult instead ? — Ranjith
Doesn't that mean that the response's entity stream is empty or has already been consumed? But that shouldn't happen, if you get a response at all, it should contain some entity, no? Anything in the server logs? — jjaderberg

Wanlu Wang Wanlu Wang · Accepted Answer · 2015-07-08T16:34:32

I met exactly the same problem. After 3 hours debugging, finally found the problem:

RestAPI graphdb1 = new RestAPIFacade(dbpath);

You not only need to provide dbpath but also your user name and password (default user name and password both are neo4j)

RestAPI graphdb1 = new RestAPIFacade(dbpath, "neo4j", "neo4j");

Error reading JSON Cypher and Rest API Neo4j

1 Answers