question on return type

[ritwik roy]

hi all
Byte is a wrapper object, not a primitive. But in the code given below if we
try to catch that wrapper object with the primitive 'int', then there will not be any error. why!!!
class C1
{
int m1()
{
Byte b=7;
return b;
}

public static void main(String arg[])
{
C1 c=new C1();
int p=c.m1();
System.out.println(p);
}
}

[Aurelio Jr. Pascual]

thats the new feature of J2SE 5.0 called auto-boxing and auto-unboxing, before J2SE 5.0 that code will give a compiler error

[ritwik roy]

hi!Aurelio
what is this auto-boxing and auto-unboxing. It is applicable to all wrapper Objects and primitives or in some particular cases???
plz send some related links......

[Naresh Saw]

hi all

if u people r preparing for scjp 1.4, plz don't use jdk1.5 because here this type of code will compile and run without error due to autoboxing and autounboxing.

prior to jdk1.5 :

this code

Byte b = 26; //1
System.out.printlnn(b); //2

was an error but in jdk1.5

when we compile, the compiler automatically create an object of type Byte(called autoboxing).

bye

[Akhilesh Trivedi]

Hi Ritwik!
You can find about boxing and unboxing in JLS, here.

I dont know under what circumstances these conversions are automatic and non-automatic. Any further links???

[marc weber]

Originally posted by ritwik roy:
...plz send some related links......

Sun - Java 1.5 in a Nutshell

[ritwik roy]

thanks Naresh!
i m preparing for scjp1.4 ,but i have been using jdk1.5 for the last 2 months. now my question is that suppose in the real exam(scjp1.4) i face such type of problem, then what should i do. go for the compiler error option.....or utilize this type of latest technology.....
what r the other things which i have not got any error in jdk1.5 but will get if i use jdk1.4..
if u know some points, plz send me..

[Srinivasa Raghavan]

No you should go for only "compiler error " if you are writing 1.4

[Naresh Saw]

srinivan is right. don't confuse with such question and keep in mind we r going for 1.4 not 1.5 dear.