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This noncompliant code example, derived from Flanagan \[[Flanagan 2005|AA. Bibliography#Flanagan 05]\], has two variables, with no guarantees regarding their current values. The code must validate its data and then check whether {{array\[i\]}} is nonnegative. |
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int array[]; // may be null
int i; // may be a valid index for array
if (array != null &
i >= 0 & i < array.length &
array[i] >= 0) {
// handle array
} else {
// handle error
}
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This code can fail due to the very errors it is attempting to prevent. When {{array}} is null or when {{i}} is not a valid index, the reference to {{array\[i\]}} will cause a {{NullPointerException}} or an {{ArrayIndexOutOfBoundsException}} to be thrown. This happens because the {{&}} operator fails to prevent evaluation of its right operand, even when evaluation of its left operand proves that the right operand is invalid. |
Compliant Solution (Use &&)
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