Why is comparing floats inconsistent in Java?

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The difference is that 6.5 can be represented exactly in both float and double, whereas 3.2 can’t be represented exactly in either type. and the two closest approximations are different.

An equality comparison between float and double first converts the float to a double and then compares the two. So the data loss.

You shouldn’t ever compare floats or doubles for equality; because you can’t really guarantee that the number you assign to the float or double is exact.

This rounding error is a characteristic feature of floating-point computation.

Squeezing infinitely many real numbers into a finite number of bits
requires an approximate representation. Although there are infinitely
many integers, in most programs the result of integer computations can
be stored in 32 bits.

In contrast, given any fixed number of bits,
most calculations with real numbers will produce quantities that
cannot be exactly represented using that many bits. Therefore the
result of a floating-point calculation must often be rounded in order
to fit back into its finite representation. This rounding error is the
characteristic feature of floating-point computation.

Check What Every Computer Scientist Should Know About Floating-Point Arithmetic for more!

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