$ java WideningAndBigIntegerDemo

=== Widening to long fixes the int-range overflow from OverflowWrapDemo ===
int:  Integer.MAX_VALUE + 1        = -2147483648  (wrong)
long: (long) Integer.MAX_VALUE + 1 = 2147483648  (correct)

=== Widening only raises the ceiling - long still overflows eventually ===
Long.MAX_VALUE + 1 = -9223372036854775808  (wrapped to Long.MIN_VALUE - same bug, bigger numbers)

=== BigInteger never overflows - it grows to fit the true value ===
BigInteger.valueOf(Long.MAX_VALUE).add(ONE) = 9223372036854775808
BigInteger.valueOf(2).pow(100)              = 1267650600228229401496703205376
(that value has no exact long or int representation at all)