Not case sensitive boolean

[podonga poron]

public class Practice {
public static void main(String... args){
Boolean b = new Boolean("tRUe");
System.out.printf("%b", b);
}
}

that prints true !

Java wasn't case sensitive, what do i miss ?

[Bear Bibeault]

What does the Javadoc have to say about it?

[Henry Wong]

Java is case sensitive -- by this, it is refering to the tokens. The method names, the class names, the variable names, the keywords, etc.

Strings are also case sensitive, but so what... strings should always be case sensitive, even if the language is not. It is kinda silly to not be able to write a program that distinguish case of strings.

In this case, it is a string, so... so what? ... but to answer your question, how the Boolean class behaves is defined in the JavaDoc. Here is the relevent excerpt.

public Boolean(String s)

Allocates a Boolean object representing the value true if the string argument is not null and is equal, ignoring case, to the string "true". Otherwise, allocate a Boolean object representing the value false.

Examples:
new Boolean("True") produces a Boolean object that represents true.
new Boolean("yes") produces a Boolean object that represents false.

Henry

[podonga poron]

In this case, it is a string, so... so what?

So it will be case sensitive but is NOT

[Bear Bibeault]

Did you read the Javadoc that I referenced and Henry copied into his reply?

[Wirianto Djunaidi]

Podon, read the excerpt that Henry posted carefully.

[podonga poron]

class foo {
public static void main(String... args){
String s1 = "true";
String s2 = "TrUE";
System.out.println((s1==s2)?"YES":"NO");
System.out.println((s1.equals(s2))?"YES":"NO");
}
}

Prints, NO and NO

i don't understand the Javadoc the only thing it does is confuse me more, i will ask this question to my instructor, dont worry thanks anyway

[Henry Wong]

i don't understand the Javadoc the only thing it does is confuse me more, i will ask this question to my instructor, dont worry thanks anyway

That is because you changed the question. Strings are case sensitive, which is why you second example says NO. The Boolean class parses strings to booleans in a case insensitive way, which is why your first example prints true.

You can't assume something is always case sensitive or case insensitive. You have to also know how they are implemented -- which is stated in the JavaDoc.

Henry

[podonga poron]

now i understand thanks !

[Ilja Preuss]

And this is how it's implemented:

public Boolean(String s) {
  this(toBoolean(s));
}
 
private static boolean toBoolean(String name) { 
  return ((name != null) && name.equalsIgnoreCase("true"));
}

Note that they could have shortened that line to

return "true".equalsIgnoreCase(name);

added an "e" to turn "not" into "note" for clarity
[ June 26, 2008: Message edited by: Frank Carver ]

[podonga poron]

Is because the equalsIgnoreCase method !

hey thanks now is VERY clear