asmhatreandClaude Sonnet 5
af615cc17c
Silent int/long overflow reproduced with real numbers, the Math *Exact() family (addExact/subtractExact/multiplyExact/incrementExact/decrementExact/ negateExact/toIntExact/absExact) with the abs(MIN_VALUE) trap absExact exists to catch, widening to long vs BigInteger, and the XOR-based overflow bit trick Math.addExact uses internally, cross-checked against BigInteger ground truth over 100k random int pairs per JUnit repeat. Co-Authored-By: Claude Sonnet 5 <[email protected]> Claude-Session: https://claude.ai/code/session_01FhzLY5p6okFva3qsnsRyvM
17 lines
748 B
Plaintext
17 lines
748 B
Plaintext
$ java OverflowWrapDemo
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=== int addition wraps silently past Integer.MAX_VALUE ===
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Integer.MAX_VALUE = 2147483647
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Integer.MAX_VALUE + 1 = -2147483648 (wrapped to Integer.MIN_VALUE, no exception)
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Integer.MIN_VALUE = -2147483648
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=== A realistic case: summing item prices in cents overflows int ===
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priceCents * quantity = 1800000000 * 2 = -694967296 (should be 3,600,000,000 - this is wrong, and no exception was thrown)
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=== Multiplication overflows just as silently as addition ===
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100000 * 100000 = 1410065408 (true value is 10,000,000,000)
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=== long has the same problem, just a much higher ceiling ===
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Long.MAX_VALUE = 9223372036854775807
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Long.MAX_VALUE + 1 = -9223372036854775808 (wrapped to Long.MIN_VALUE)
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