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From "Henning P. Schmiedehausen" <...@intermeta.de>
Subject Re: svn commit: r233505 - in /jakarta/commons/proper/configuration/trunk/src:
Date Mon, 22 Aug 2005 12:48:14 GMT
Brett Porter <brett@apache.org> writes:

>How?

>if keyBuffer is null (which it isn't, the constructor initialises it),
>String.valueOf( keyBuffer ) would be an NPE as well. toString() should
>not return null and won't for a StringBuffer.

What the...?????

--- cut ----
import java.io.File;

public class test {
    public static void main(String[] args) throws Exception {
        System.out.println(String.valueOf((Object) null));
    }
}
--- cut ----

[henning@forge tmp]$ javac test.java
[henning@forge tmp]$ java -version
java version "1.5.0_02"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.5.0_02-b09)
Java HotSpot(TM) Client VM (build 1.5.0_02-b09, mixed mode, sharing)
[henning@forge tmp]$ java test
Exception in thread "main" java.lang.NullPointerException
        at java.lang.String.<init>(String.java:173)
        at java.lang.String.valueOf(String.java:2591)
        at test.main(test.java:5)

[henning@forge tmp]$ javac test.java
[henning@forge tmp]$ java -version
java version "1.4.2_08"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.4.2_08-b03)
Java HotSpot(TM) Client VM (build 1.4.2_08-b03, mixed mode)
[henning@forge tmp]$ java test
null

Oh fsck, Sun, please, please, please don't tell me that you screwed
_that_ one up.....

The javadoc even states:

http://java.sun.com/j2se/1.5.0/docs/api/java/lang/String.html#valueOf(java.lang.Object)

--- cut ---
valueOf

public static String valueOf(Object obj)

    Returns the string representation of the Object argument.

    Parameters:
        obj - an Object. 
    Returns:
        if the argument is null, then a string equal to "null";
        otherwise, the value of obj.toString() is returned.
    See Also:
        Object.toString()

--- cut ---

Congrats. You found a bug. IMHO.

This is BTW one of my personal mnemonics. 

I do replace foobar.toString() with String.valueOf(foobar) because up
until a few seconds ago I was under the firm impression, that
String.valueOf(...) could _never_ throw NPE. This is a constant source
of sorrow with code that I'm working on, because often co-workers tell
me "that can never be null". Yeah, unless, some weird condition
happens that was not tested for and surfaced after customer
installation. Better safe than sorry. Defensive programming... :-)

	Regards
		Henning

-- 
Dipl.-Inf. (Univ.) Henning P. Schmiedehausen          INTERMETA GmbH
hps@intermeta.de        +49 9131 50 654 0   http://www.intermeta.de/

RedHat Certified Engineer -- Jakarta Turbine Development  -- hero for hire
   Linux, Java, perl, Solaris -- Consulting, Training, Development

		      4 - 8 - 15 - 16 - 23 - 42

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