Return from HashMap<String, String> when no key
JavaJava Problem Overview
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?
Java Solutions
Solution 1 - Java
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.
Solution 2 - Java
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.
Solution 3 - Java
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.