asmhatreandClaude Sonnet 5.5
f80e1079a8
Co-Authored-By: Claude Sonnet 5.5 <[email protected]> Claude-Session: https://claude.ai/code/session_017ic4b7rnC7jppGGdHGESvy
10 lines
599 B
Plaintext
10 lines
599 B
Plaintext
null keys and values: HashMap allows, ConcurrentHashMap rejects
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HashMap.put(null, ..) accepted; the null key lives in table[0]: true
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HashMap.get(null) = for-null-key
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HashMap.get("present-but-null") = null containsKey = true
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HashMap.get("absent") = null containsKey = false <- get() alone cannot tell these two apart
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ConcurrentHashMap put(null, v), put(k, null), get(null), containsKey(null), merge(k, null, f): all throw NullPointerException
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compute(k, (k,v) -> null) removes the entry instead: containsKey(k) = false
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