Java's Defualt Literal Types (Whole number literals defaults to int?)

Question

Hello guys, its my first Post here, just want to ask
is java whole number literals defaults to int?
check these codes
---code 1:---
Java Code:
1
byte b = 10;
//code 1 works
---code 2:---
void someMethod(byte a,byte b)
System.out.println(a+b);
then I use it
someMethod(10,5);
//code 2 doesn't work, it yields an error
Exception in thread "main" java.lang.Error: Unresolved compilation problem:
The method sum(byte, byte) in the type Test is not applicable for the arguments (int, int)
now these are my questions
1. does java whole number literals defaults to int? (I think so, basing on the code)
2. if question no. 1 is true, then why code 1 worked? it shouldn't right, coz its a downward cast (from int to byte).
3. what really happens under the hood?
by the way, the jdk version I used is 1.7.0
Thank you guys in advance

Answer 1

915343 wrote:
Hello guys, its my first Post here, just want to ask
is java whole number literals defaults to int?Yes.
1
byte b = 10;
//code 1 worksThe literal expression *10* is an int. But it's a compile-time constant that fits into a byte, so the assignment is okay without a cast.
---code 2:---
void someMethod(byte a,byte b)
System.out.println(a+b);
then I use it
someMethod(10,5);
//code 2 doesn't work, it yields an errorBecause 10 and 5 are ints, not bytes, and there's no method that can take int as args. The automatic narrowing conversion that takes place for assignment does not come into play when finding a matching method signature.
1. does java whole number literals defaults to int? (I think so, basing on the code)Yes.
3. what really happens under the hood?Read the JLS for those details.
http://java.sun.com/docs/books/jls/third_edition/html/lexical.html#3.10
http://java.sun.com/docs/books/jls/third_edition/html/conversions.html
http://java.sun.com/docs/books/jls/third_edition/html/expressions.html#15.12
Edited by: jverd on Feb 17, 2012 3:49 PM