Java™ Application Development on Linux - Dator

3.2 Fundamental Language Elements79System.out.println("The answer is "+val);“But what if val is not a String?” we hear you asking. Don’t worry, theJava compiler is smart enough to know, that when you are adding with aString argument it must convert the other argument to a String, too. So forany Object, it will implicitly call its toString() method. For any primitivetype (e.g., int or boolean), the compiler will convert it to a String, too.The third of the three output methods, printf(), sounds very familiarto C/C++ programmers, but be warned:• It is only available in Java 5.0 7 and after.• It is similar but not identical to the C/C++ version.Perhaps the most significant enhancement to printf() is its additionalsyntax for dealing with internationalization. It’s all well and good to translateyour Strings to a foreign language, but in doing so you may need to changethe word order and thus the order of the arguments to printf(). For example,the French tend to put the adjective after rather than before the noun (as we doin English). We say “the red balloon” and they say “le balloon rouge.” If yourprogram had Strings for adjective and noun, then a printf() like this:String format = "the %s %s\n";System.out.printf(format, adjective, noun);wouldn’t work if you translate just the format String:String format = "le %s %s\n";System.out.printf(format, noun, adjective);You’d like to be able to do the translation without changing the code in yourprogram. 8 With the Java version of printf(), there is syntax for specifyingwhich argument corresponds to which format field in the format string. It uses7. Remember, you’ll need the -source 5.0 option on the command line.8. Java has good support for internationalization, another topic for which we don’t have thetime. The ability to translate the strings without otherwise modifying the program is a crucialpart to internationalization, and the printf() in Java 5.0 is certainly a help in this regard. Ina similar vein, the Eclipse IDE, covered in Chapter 10, includes a feature to take all stringconstants and convert them to external properties at a stroke, making internationalization mucheasier to do.