Return Value of put() in HashMap

Question

I was having trouble understanding the explanation for return value of put() in a HashMap:

  private Map<Bookmark, Integer> mDevice = new HashMap<String, Integer>();

    String abc = "two"
    Integer ret = mDevice.put(abc, ONLINE);

Am I correct in saying the following:

1. if abc key already exists with value OFFLINE, ret is equal to OFFLINE.
2. if abc key already exists with value ONLINE, ret is equal to ONLINE.
3. if abc key did not exist, then ret is equal to null.

Answer 1

The method put has a return type same with the value:

    @Override
    public V put(K key, V value) {
        return putImpl(key, value);
    }

The method associates the specified value with the specified key in this map. If the map previously contained a mapping for the key, the old value is replaced.

It returns the previous value associated with key, or null if there was no mapping for key.So, your points are right.

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