How to search a document and remove field from it in mongodb using java? -

i have device collection.

{    "_id" : "10-100-5675234",    "_type" : "device",    "alias" : "new alias name",     "claimcode" : "fg755df8n",     "hardwareid" : "serail02",    "isclaimed" : "true",    "model" : "vmb3010",     "userid" : "5514f428c7b93d48007ac6fd"   } 

i want search document _id , update after removing field userid result document. trying different ways none of them working. please me.

you can remove field using $unset mongo-java driver in way:

    mongoclient mongo = new mongoclient("localhost", 27017);     db db = (db) mongo.getdb("testdb");     dbcollection collection = db.getcollection("collection");     dbobject query = new basicdbobject("_id", "10-100-5675234");     dbobject update = new basicdbobject();     update.put("$unset", new basicdbobject("userid",""));     writeresult result = collection.update(query, update);     mongo.close(); 

find out more @ : http://www.journaldev.com/4334/mongodb-update-document-set-all-example-mongo-shell-java-driver