Long is 8 bytes in size, while how can it be "promoted" for float (4 bytes) in JAVA?

Question

I read that in Java a long type can be raised by float and double ( http://www.javatpoint.com/method-overloading-in-java ). I wanted to ask that a long integer takes 8 bytes of memory in JAVA and a float takes 4 bytes, how does it work? Is it not possible that we can face data loss if we advance this way?

It is also noticeable that all promotions of a different type belong to a primitive type of a smaller size to similar or larger data types.

• byte for short, int, long, float or double
• short for int, long, float or double
• char for int, long, float or double
• int for long, float or double
• long swim or double _______________ Exclusively In the case of Float
• float for double

Answer 1

float is represented differently than integer types. For more information about the floating type, read the following: https://en.wikipedia.org/wiki/Single-precision_floating-point_format . The content generated down will look like this: the floating point format consists of a signed bit, 8 bits for the exponent and 23 bits for the fractional part of the value. The value is calculated as follows: (-1) ^ signbit * 1.fractionalpart * 2 ^ (exponent - 127). Thus, this algorithm allows us to represent larger values ​​than the 64-bit integral type.

Answer 2

long uses more bytes, but has a smaller range: while long cannot exceed 2 ⁶³ float can go up to about 2 ¹²⁷ It is obvious that the extension of the range is associated with low accuracy, but since the range of float larger, the conversion from long to float is an advancement.

Answer 3

This quick test should show why:

 public class Main { public static void main(String[] args) { System.out.println("Float: " + Float.MAX_VALUE); System.out.println("Long: " + Long.MAX_VALUE); } } 

Ouput:

 Float: 3.4028235E38 Long: 9223372036854775807 

Pay attention to the scientific notation in the Float line. Float takes up less space, but due to its presentation, it can hold up to a larger number than Long.