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What Map.getOrDefault returns for a key that is present but mapped to null - which of the following is true?

  • A.NullPointerException.
  • B.The first non-null value in the map.
  • C.null.
  • D.The supplied default.

Answer: C

The javadoc defines the default as applying when the map contains no mapping for the key, and a key mapped to null is a mapping. So the method removes the need for a containsKey check only if null values are never stored, which is one more reason to avoid them.

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