I would like to retrieve every document with a patchName(String), which contains a given phrase. E.g. "When the user submits a keyword "S2A", he will acquire all matching documents with patch names i.e., "patchName" : "S2A_MSIL2A_20170613T101031_0_64". Since I would like that the phrase is contained into the patch name, I decided to go with $regex, since a text index searches only exact phrases. I managed it to submit the query in the mongodb shell, however, I am not able to reproduce it inside the Spring Boot Repository class at server-side. Hereby I attach some screenshots:   And here is the analogous query, submitted from Spring Boot Repository class:   And this is how I invoke it (p.s. I tried several approaches, but still nothing): Whichever approach I take, it still does not work. Even if I submit the exact patch name of the document, it does not retrieve it. Hereby I provide you with two example documents (the data originates from the BigEarthNet archive ( http://bigearth.net/): { "_id" : ObjectId("60531c9be17ae9783919549b"), "type" : "Feature", "location" : [ [ 20.9996003792675, 63.3486882292739 ], [ 20.9996003792675, 63.3379164659186 ], [ 21.0235688072459, 63.3379164659186 ], [ 21.0235688072459, 63.3486882292739 ], [ 20.9996003792675, 63.3486882292739 ] ], "properties" : { "patchName" : "S2A_MSIL2A_20170613T101031_0_63", "labels" : [ "f" ], "acquisitionDate" : ISODate("2017-01-13T09:10:31Z") } , "_class" : "com.tuberlin.dbpro.models.database.MetaJson" } { "_id" : ObjectId("60531c9be17ae9783919549c"), "type" : "Feature", "location" : [ [ 20.9996005286705, 63.3379184119332 ], [ 20.9996005286705, 63.3271466330944 ], [ 21.0235599998921, 63.3271466330944 ], [ 21.0235599998921, 63.3379184119332 ], [ 20.9996005286705, 63.3379184119332 ] ], "properties" : { "patchName" : "S2A_MSIL2A_20170613T101031_0_64", "labels" : [ "f" ], "acquisitionDate" : ISODate("2017-01-13T09:10:31Z") } , "_class" : "com.tuberlin.dbpro.models.database.MetaJson" }