Autoboxing

[Ian Lubelsky]

I am trying to test a piece of code which converts a string to an integer through autoboxing.

This works:

public class Test

{
    public static void main(String[] args)
    {
	Integer value = new Integer (args[0]);
        System.out.println(value);
    }
}

But this doesn't

public class Test

{
    public static void main(String[] args)
    {
	Integer value = args[0];
	System.out.println(value);
    }
}

From what I read and understood, is the second method can now be written, even though the compiler will interpret it as the first example I gave. However, when I compile the second example, I get an Incompatible Types error. It says Found java.lang.String, but Required java.lang.Integer.

Would I just be better off doing a..... Integer value = Integer.parseInt(args[0]); instead?

[Henry Wong]

Autoboxing is for the conversion of a primative type to its wrapper, and vice versa. It has nothing to do with String to Integer conversion.

Henry

[Ian Lubelsky]

After re-reading the section, that is what I figured. So I'm just going to use: Integer value = Integer.parseInt(args[0]);

[Campbell Ritchie]

That looks good, but it might be preceded by a test like this

 . . .
    public static void main(String[] args)
    {
       if (args.length == 0)
       {
          System.err.printf("Please enter a command line argument%nUsage: java Test 123%n");
          System.exit(1);
       }
 . . .

You may also wish to test for a NumberFormatException.

[Vivek Saha]

Can any one please help me to understand the concept of "AUTOBOXING & UNBOXING" .......................?

[Vivek Saha]

IS following the SCJP 6 book by--- Kathy & Bert enough for securing 100% marks in da SCJP exam???

[Janeice DelVecchio]

Vivek, please start a new thread for your questions. Asking questions in someone else's thread is hijacking and not very nice to the original poster.

SCJP exam questions should be asked in the SCJP forum.

A simple google search of autoboxing and Java should get you started.

[Rob Spoor]

And while we're making remarks on your posts:

Vivek Saha wrote:IS following the SCJP 6 book by--- Kathy & Bert enough for securing 100% marks in da SCJP exam???

1) UseRealWords. Not "da" but "the".
2) Nothing can guarantee you a 100% score in any exam.