Why long literal can be assigned to float variable while float datatype uses less memory?

Question

float uses 32 bits and long uses 64 bits. Why is this allowed by the compiler then?

float x = 5555555555555555555L;

Answer 1

The range of float is broader than the range of long. So while you can certainly lose precision with an assignment like this (and can when assigning a long value to double too), the general magnitude is already representable - so there's never be a need to throw an exception due to it being out of range, for example.

The JLS (section 5.1.2) says this:

A widening primitive conversion from int to float, or from long to float, or from long to double, may result in loss of precision - that is, the result may lose some of the least significant bits of the value. In this case, the resulting floating-point value will be a correctly rounded version of the integer value, using IEEE 754 round-to-nearest mode (§4.2.4).