Willie

In Java programming language, when a value is assigned to a variable of different types, one of the 2 cases can occur:

Widening (Promotion)

• Value has a smaller range compared to the variable
• Converted automatically by Java compiler

Narrowing (Demotion)

• Value has a larger range compared to the variable
• Explicit type casting by the programmer is needed

Example (without type casting):

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double d;
int i = 31415;
 
d = i / 10000;
System.out.println(d);

This will output:

3.0

We are expecting the output to be 3.1415 in this case.

Example (with type casting):

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double d;
int i = 31415;
 
d = (double) i / 10000;
System.out.println(d);

This will output:

3.1415

Here, we type cast int i to double type so that the calculation of the result will match the double type of variable d.