Precision lost in float value using java

Question

Given below the test code and its output. When I get float value from number value, precision is lost.. Can anyone tell me why this behaviour and also how to handle this?

Answer 1

Decimal literals like the one you have typed default to type double, not float. java.lang.Number also uses doubles by default. If you were to replace that with java.lang.Number numberVal = 676543.21f; I would expect the same level of precision loss from both. Alternatively, replace float floatVal = numberVal.floatValue(); with double doubleVal = numberVal.doubleValue(); In order not to lose precision.

EDIT, as an example, try running:

Number num = 676543.21;
System.out.println(num); //676543.21
System.out.println(num.doubleValue()); //676543.21
System.out.println(num.floatValue()); //676543.2 <= loses the precision

to see the difference in precision of the types

Float.MAX_VALUE returns the largest value that a float can ever hold. any higher will overflow. If you look carefully, you'll see an 'E' in its textual representation. This is standard index form, that 'E' means "multiply by 10 to the power of whatever number follows the E" (or in java-speak *pow(10, numberAfterE))