java - Why i am getting type mismatch: cannot convert from int to byte

Question

class Test
{  
   public static void main(String[] args) 
   { 
     byte t1 = 111;
     byte t2 =11;
     byte t3 = t1+t2;

     System.out.println(t1+t2);   

   }  
}  

In eclipse it is showing error cannot convert from int to byte.Here sum is 122 which range in the byte range.So why i am getting this error here.

Thanks in advance...

Answer 1

When you do mathematical operations on byte, Java do Widening( automatic type promotion) to byte(implicitly up casted) to integer this case. so when you perform

 byte t3 = t1+t2; //  t1+t2; will be evaluated as integer.

As t1+t2 result is wider than byte so you need to downcast it to byte.

To remove compilation error.

 byte t3 = (byte) (t1+t2); // typecast to byte

For more information please read JLS 5.1.2