Touring Language APIs - Beginning Java 7 - page 313

class AbsByteShort
{
static byte abs(byte b)
{
return (b < 0) ? (byte) -b : b;
}
static short abs(short s)
{
return (s < 0) ? (short) -s : s;
}
public static void main(String[] args)
{
byte b = -2;
System.out.println(abs(b)); // Output: 2
short s = -3;
System.out.println(abs(s)); // Output: 3
}
}
Listing 4-2 ' s (byte) and (short) casts are necessary because -b converts b 's
valuefroma byte toan int ,and -s converts s 'svaluefroma short toan int .In
contrast,thesecastsarenotneededwith (b < 0) and (s < 0) ,whichautomatically
cast b 's and s 's values to an int before comparing them with int -based 0 .
Tip Theirabsencefrom Math suggeststhat byte and short arenotveryusefulin
methoddeclarations.However,thesetypesareusefulwhendeclaringarrayswhoseele-
mentsstoresmallvalues(suchasabinaryfile'sbytevalues).Ifyoudeclaredanarray
of int or long tostoresuchvalues,youwouldendupwastingheapspace(andmight
even run out of memory).
WhilesearchingthroughtheJavadocumentationforthe java.lang package,you
will probablyencounter aclass named StrictMath .Apartfromalongername, this
class appears to be identical to Math . The differences between these classes can be
summed up as follows:
• StrictMath 's methods return exactly the same results on all platforms. In
contrast,someof Math 'smethodsmightreturnvaluesthatvaryeversoslightly
from platform to platform.