A variable that never changes value is a constant. In Java, you can explicitly declare a variable as a constant by using the final keyword.
For example:
final int M = 3;
The word final indicates that the variable M of type int cannot change its value to 3.
In this case M is said to be a constant and not a variable.
Constants are useful for creating more flexible and maintainable applications. They help prevent errors when a numeric or other value needs to be used in multiple places within the code.
As is similarly the case in all programming languages, keywords in the
Java cannot be used as variable or constant names, so words like final, int and we will see while, do and others
cannot be used as variable or constant names.
We’ll see in future posts that I can use final in other contexts as well.