Core Java · interview question
What would happen if you try to add a null key to a TreeMap?
Multiple choiceHardchapter-4-curatedpremiumcore-javacode-reading-with-collections
Answer and explanation
Correct answer
D. ClassCastException
Why
TreeMap requires keys to be comparable to maintain order. Adding a null key would result in a ClassCastException since null cannot be compared to other keys.
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