Conversions and Promotions - The Java Language Specification - page 86

b. The value must be too large (a positive value of large magnitude or positive
infinity), and the result of the first step is the largest representable value of
type int or long .
2. In the second step:
• If T is int or long , the result of the conversion is the result of the first step.
• If T is byte , char , or short , the result of the conversion is the result of a narrowing
conversion to type T (§ 5.1.3 ) of the result of the first step.
Example 5.1.3-1. Narrowing Primitive Conversion
Click here to view code image
class Test {
public static void main(String[] args) {
float fmin = Float.NEGATIVE_INFINITY;
float fmax = Float.POSITIVE_INFINITY;
System.out.println("long: " + (long)fmin +
".." + (long)fmax);
System.out.println("int: " + (int)fmin +
".." + (int)fmax);
System.out.println("short: " + (short)fmin +
".." + (short)fmax);
System.out.println("char: " + (int)(char)fmin +
".." + (int)(char)fmax);
System.out.println("byte: " + (byte)fmin +
".." + (byte)fmax);
}
}
This program produces the output:
long: -9223372036854775808..9223372036854775807
int: -2147483648..2147483647
short: 0..-1
char: 0..65535
byte: 0..-1
The results for char , int , and long are unsurprising, producing the minimum and max-
imum representable values of the type.
The results for byte and short lose information about the sign and magnitude of the nu-
meric values and also lose precision. The results can be understood by examining the
low order bits of the minimum and maximum int . The minimum int is, in hexadecimal,
0x80000000 , and the maximum int is 0x7fffffff . This explains the short results, which are