Here is a copy of code which works fine for me,

import json

with open("test.json") as json_file:
    json_data = json.load(json_file)
    print(json_data)

with the data

{
    "a": [1,3,"asdf",true],
    "b": {
        "Hello": "world"
    }
}

You may want to wrap your json.load line with a try catch, because invalid JSON will cause a stacktrace error message.

Just going to add a simple example to what everyone has explained,

json.load()

json.load can deserialize a file itself i.e. it accepts a file object, for example,

# open a json file for reading and print content using json.load
with open("/xyz/json_data.json", "r") as content:
  print(json.load(content))

will output,

{u'event': {u'id': u'5206c7e2-da67-42da-9341-6ea403c632c7', u'name': u'Sufiyan Ghori'}}

If I use json.loads to open a file instead,

# you cannot use json.loads on file object
with open("json_data.json", "r") as content:
  print(json.loads(content))

I would get this error:

TypeError: expected string or buffer

json.loads()

json.loads() deserialize string.

So in order to use json.loads I will have to pass the content of the file using read() function, for example,

using content.read() with json.loads() return content of the file,

with open("json_data.json", "r") as content:
  print(json.loads(content.read()))

Output,

{u'event': {u'id': u'5206c7e2-da67-42da-9341-6ea403c632c7', u'name': u'Sufiyan Ghori'}}

That's because type of content.read() is string, i.e. <type 'str'>

If I use json.load() with content.read(), I will get error,

with open("json_data.json", "r") as content:
  print(json.load(content.read()))

Gives,

AttributeError: 'str' object has no attribute 'read'

So, now you know json.load deserialze file and json.loads deserialize a string.

Another example,

sys.stdin return file object, so if i do print(json.load(sys.stdin)), I will get actual json data,

cat json_data.json | ./test.py

{u'event': {u'id': u'5206c7e2-da67-42da-9341-6ea403c632c7', u'name': u'Sufiyan Ghori'}}

If I want to use json.loads(), I would do print(json.loads(sys.stdin.read())) instead.

The "s" is an abbreviation for "string". "dump__s__" is read as "dump string". "load__s__" = "load string". Otherwise these methods want a file-like object. This convention is scattered throughout python and even 3rd-party packages.

Ok first you should print your object so that you can read it:

>>> from pprint import pprint
>>> output = [{'in_reply_to_status_id_str': None, 'in_reply_to_screen_name': None, 'retweeted':     False, 'in_reply_to_status_id': None, 'contributors': None, 'favorite_count': 0, 'in_reply_to_user_id': None, 'coordinates': None, 'source': '<a href="http://twitter.com" rel="nofollow">Twitter Web Client</a>', 'geo': None, 'retweet_count': 0, 'text': 'Tweeting a url \nhttp://t.co/QDVYv6bV90', 'created_at': 'Mon Sep 01 19:36:25 +0000 2014', 'entities': {'symbols': [], 'user_mentions': [], 'urls': [{'expanded_url': 'http://www.isthereanappthat.com', 'display_url': 'isthereanappthat.com', 'url': 'http://t.co/QDVYv6bV90', 'indices': [16, 38]}], 'hashtags': []}, 'id_str': '506526005943865344', 'in_reply_to_user_id_str': None, 'truncated': False, 'favorited': False, 'lang': 'en', 'possibly_sensitive': False, 'id': 506526005943865344, 'user': {'profile_text_color': '333333', 'time_zone': None, 'entities': {'description': {'urls': []}}, 'url': None, 'profile_background_image_url': 'http://abs.twimg.com/images/themes/theme1/bg.png', 'profile_background_image_url_https': 'https://abs.twimg.com/images/themes/theme1/bg.png', 'protected': False, 'default_profile_image': True, 'utc_offset': None, 'default_profile': True, 'screen_name': 'KickzWatch', 'follow_request_sent': False, 'following': False, 'profile_background_color': 'C0DEED', 'notifications': False, 'description': '', 'profile_sidebar_border_color': 'C0DEED', 'geo_enabled': False, 'verified': False, 'friends_count': 40, 'created_at': 'Mon Sep 01 16:29:18 +0000 2014', 'is_translator': False, 'profile_sidebar_fill_color': 'DDEEF6', 'statuses_count': 4, 'location': '', 'id_str': '2784389341', 'followers_count': 4, 'favourites_count': 0, 'contributors_enabled': False, 'is_translation_enabled': False, 'lang': 'en', 'profile_image_url': 'http://abs.twimg.com/sticky/default_profile_images/default_profile_6_normal.png', 'profile_image_url_https': 'https://abs.twimg.com/sticky/default_profile_images/default_profile_6_normal.png', 'id': 2784389341, 'profile_use_background_image': True, 'listed_count': 0, 'profile_background_tile': False, 'name': 'Maktub Destiny', 'profile_link_color': '0084B4'}, 'place': None}]
>>> pprint(output)
[{'contributors': None,
  'coordinates': None,
  'created_at': 'Mon Sep 01 19:36:25 +0000 2014',
  'entities': {'hashtags': [],
               'symbols': [],
               'urls': [{'display_url': 'isthereanappthat.com',
                         'expanded_url': 'http://www.isthereanappthat.com',
                         'indices': [16, 38],
                         'url': 'http://t.co/QDVYv6bV90'}],
               'user_mentions': []},
  'favorite_count': 0,
  'favorited': False,
  'geo': None,
  'id': 506526005943865344,
  'id_str': '506526005943865344',
  'in_reply_to_screen_name': None,
  'in_reply_to_status_id': None,
  'in_reply_to_status_id_str': None,
  'in_reply_to_user_id': None,
  'in_reply_to_user_id_str': None,
  'lang': 'en',
  'place': None,
  'possibly_sensitive': False,
  'retweet_count': 0,
  'retweeted': False,
  'source': '<a href="http://twitter.com" rel="nofollow">Twitter Web Client</a>',
  'text': 'Tweeting a url \nhttp://t.co/QDVYv6bV90',
  'truncated': False,
  'user': {'contributors_enabled': False,
           'created_at': 'Mon Sep 01 16:29:18 +0000 2014',
           'default_profile': True,
           'default_profile_image': True,
           'description': '',
           'entities': {'description': {'urls': []}},
           'favourites_count': 0,
           'follow_request_sent': False,
           'followers_count': 4,
           'following': False,
           'friends_count': 40,
           'geo_enabled': False,
           'id': 2784389341,
           'id_str': '2784389341',
           'is_translation_enabled': False,
           'is_translator': False,
           'lang': 'en',
           'listed_count': 0,
           'location': '',
           'name': 'Maktub Destiny',
           'notifications': False,
           'profile_background_color': 'C0DEED',
           'profile_background_image_url': 'http://abs.twimg.com/images/themes/theme1/bg.png',
           'profile_background_image_url_https': 'https://abs.twimg.com/images/themes/theme1/bg.png',
           'profile_background_tile': False,
           'profile_image_url': 'http://abs.twimg.com/sticky/default_profile_images/default_profile_6_normal.png',
           'profile_image_url_https': 'https://abs.twimg.com/sticky/default_profile_images/default_profile_6_normal.png',
           'profile_link_color': '0084B4',
           'profile_sidebar_border_color': 'C0DEED',
           'profile_sidebar_fill_color': 'DDEEF6',
           'profile_text_color': '333333',
           'profile_use_background_image': True,
           'protected': False,
           'screen_name': 'KickzWatch',
           'statuses_count': 4,
           'time_zone': None,
           'url': None,
           'utc_offset': None,
           'verified': False}}]

From looking at this you can see that output is a list which contains a single dict. To access this you need:

>>> first_elem = output[0]

You will also see that the hashtags key in the first_elem is contained in a second level dict under the key entities:

>>> entities = first_elem['entities']
>>> pprint(entities)
{'hashtags': [],
 'symbols': [],
 'urls': [{'display_url': 'isthereanappthat.com',
           'expanded_url': 'http://www.isthereanappthat.com',
           'indices': [16, 38],
           'url': 'http://t.co/QDVYv6bV90'}],
 'user_mentions': []}

Now you are able to access hashtags:

>>> entities['hashtags']
[]

Which just happens to be the empty list.

To convert to JSON, note the comment:

>>> import json
>>> # Make sure output is the list object not a string representing the object
>>> json_string = json.dumps(output)
>>> jason = json.loads(output)
>>> jason[0]['entities']['hashtags']
[]

I think your problem is that you made output a string before you json.dumps it, meaning that json.loads will return a string, not a json object.

And @Dan's answer is correct, this is not valid JSON. It is however a valid python dict, and I'm assuming that you got it from Twitter using python then printed it.