Cannot convert char to byte

[Shainaz Tamboli]

Hi,

Can you please tell me why the below code giving me compilation error : Type mismatch

public class CharToByte {

static byte m1(){
	final char c1='\u0003';
	return c1;
}

static byte m2(char c2){
	return c2;
}

}

In above code method m1() working fine but method m2() giving compilation error.

So can you please tell me why?

Regards,
Shainaz

[Mina Daoud]

Your method m2 is declared to return a bye value (8 bits size), and it is returning a char (16 bits size)!

[naveen yadav]

size of the type does not matter the range of the values matter.

as range of character is 0 to 65536 and range of byte is -127 to 128.

byte to chat conversion
say
byte bt = -10 ;
char ch1 = bt ; //-------error , why -10 does not lie in the range of char.
char ch1 = (char) bt; //---------It is a narrow conversion Always cast.


similarly char to byte conversion
char ch = 666 ;
byte bt = ch ; //-------error , why 666 does not lie in the range of byte.
byte bt = (byte) ch; //---------It is a narrow conversion Always cast.

[Mina Daoud]

naveen yadav wrote:
size of the type does not matter the range of the values matter.

as range of character is 0 to 65536 and range of byte is -127 to 128.

byte to chat conversion
say
byte bt = -10 ;
char ch1 = bt ; //-------error , why -10 does not lie in the range of char.
char ch1 = (char) bt; //---------It is a narrow conversion Always cast.


similarly char to byte conversion
char ch = 666 ;
byte bt = ch ; //-------error , why 666 does not lie in the range of byte.
byte bt = (byte) ch; //---------It is a narrow conversion Always cast.

Yes, i am sorry. You are right.

[Bhasker Tiwari]

Hi Naveen,

You are right, But it actually does not answer the question properly,
The complete code is like below, shainaz is my friend.

class JSC201 {
  static byte m1() {
    final char c1 = '\u0001';
    return c1;                                // 1
  }
  static byte m2(final char c2) {return c2;}  // 2 - error condition
  public static void main(String[] args) {
    char c3 = '\u0001'; 
    System.out.print(""+m1()+m2(c3));         // 3
}}

So, here my question is even if the user supplies the same value as in m1(), then based on your explanation, it should cause the error.
As it is not throwing in m1().
So, as per me there is something to do with the interpretation of this in JVM, where JVM says, if the value is expected to come at runtime, then it falls in your explanation.

Please feel free to correct me.
Thanks.