Hi ,

From the java driver when I run the attached query it throws following error

com.mongodb.MongoException: Can't canonicalize query: BadValue unknown top level operator: $query
at com.mongodb.QueryResultIterator.throwOnQueryFailure(QueryResultIterator.java:214)
at com.mongodb.QueryResultIterator.init(QueryResultIterator.java:198)
at com.mongodb.QueryResultIterator.initFromQueryResponse(QueryResultIterator.java:176)
at com.mongodb.QueryResultIterator.<init>(QueryResultIterator.java:64)
at com.mongodb.DBCollectionImpl.find(DBCollectionImpl.java:86)
at com.mongodb.DBCollectionImpl.find(DBCollectionImpl.java:66)
at com.mongodb.DBCursor._check(DBCursor.java:458)
at com.mongodb.DBCursor._hasNext(DBCursor.java:546)
at com.mongodb.DBCursor.hasNext(DBCursor.java:571)
at aap.main(aap.java:57)

The code and mongodb output is here:
mongos> db.test.find({$query:{}},

{"price":10}

)

{ "_id" : 1, "price" : 10 } { "_id" : 2, "price" : 20 } { "_id" : 3, "price" : 5 } { "_id" : ObjectId("54dadd1c63108d63b47e79c3") } { "_id" : ObjectId("54e23eb9e63b0d8071b5b2af") }

{ "_id" : ObjectId("54e23ed3e63b0d8071b5b2b0")

================================================
java Code:
MongoClient mongo = new MongoClient("<Hostname>", 27017);
DB db = mongo.getDB("test");

DBCollection table = db.getCollection("test");
DBObject searchQuery = (DBObject)JSON.parse("{$query:{}},

{'price':10}

");
DBCursor cursor = table.find(searchQuery);

while (cursor.hasNext())

{ System.out.println(cursor.next()); }