What does a HashMap<String,String> return when I call map.get("key") and I don't have an entry with the key "key" in the HashMap?
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8Read the docs ... download.oracle.com/javase/6/docs/api/java/util/…Vincent Mimoun-Prat– Vincent Mimoun-Prat2011-03-07 14:05:52 +00:00Commented Mar 7, 2011 at 14:05
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3 Answers
It returns null. It's written in the documentation.
Returns: the value to which the specified key is mapped, or null if this map contains no mapping for the key
The first thing to do when you have such a specific question is to consult the documentation. Java APIs are documented reasonably well and tell you what is returned, what exceptions are thrown and what each argument means.
Comments
You can:
Check in your IDE
Map<String, String> map = new HashMap<String, String>();
map.put("foo", "fooValue");
System.out.println(map.get("bar")); // null
Check documentation - HashMap get() method description:
Returns the value to which the specified key is mapped, or null if this map contains no mapping for the key.
1 Comment
Anindya Chatterjee
again HashMap<String> is not possible in standard java library, unless you have created your own HashMap, it should be with two type arguments like Map<String, Object> map = new HashMap<String, Object>() or something like that.
Careful - If you initialize it using
Map.of(key, val, key, val)
and then do a
get('key-that-isnt-there')
then you'll get a null pointer exception.
