HowdoIremovemultipleJSONObjectsfromArrayList

list =  [
  {
    "_display_name": "Sources of Food",
    "_id": "5b"
  },
  {
    "_display_name": "Practice Test",
    "_type": "practice_quiz"
  },
  {
    "_display_name": "Challenge Test",
    "_type": "challenge_test"
  },
  {
    "_display_name": "nutrients",
    "_id": "5f232"
  }
]

from the above JSONArray, I want to get only jsonobjects containing Challenge test and Practice test. I'm using simple.org.json. My code is as follows.

if(hashmap.containsKey("_type")) {
    list.remove(hashmap);
}