How can integer and double values be the same in Java?

Question

class Test {
   public static void main(String[] args) {
     int i=1;
     double d=1.0;
     if(i==d)
        System.out.println("True") // whether any type casting happens.
     else 
        System.out.println("false");
   }
}

Answer 1

Here's a relevant quote from the JLS :

When an operator applies binary numeric promotion to a pair of operands, each of which must denote a value that is convertible to a numeric type, the following rules apply, in order:
...
2. Widening primitive conversion (§5.1.2) is applied to convert either or both operands as specified by the following rules:

- If either operand is of type double, the other is converted to double.

In your case i is converted to double in order to perform the comparison.