Narrower primitive types can be cast to wider types without any effect on the magnitude of numeric values. However, when the expressions are not strictfp, conversions from float to double may lose information about the overall magnitude of the converted value (see JLS Section 5.1.2, Widening Primitive Conversion).
Conversion from int or long to float, or long to double can lead to loss of precision (loss of least significant bits). No runtime exception occurs despite the loss.
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In this noncompliant example, an int is converted to float. Since Because a floating point number cannot be precise to 9 digits, the result of subtracting the original from this value is non-zero.
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class WideSample {
public static void main(String[] args) {
int big = 1234567890;
float approx = big;
System.out.println(big - (int)approx); //ideally this shouldis expected to be zero but it prints -46
}
}
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