To declare a variable as final, use the final keyword in the variable's declaration.
The following code declares four final variables: YES, NO, MSG, and account:
final int YES = 1; final int NO = 2; final String MSG = "message"; final Account account = new Account();
You can set the value of a final variable only once.
Setting the value of a final variable the second time will generate a compilation time error.
final int x = 10; int y = 101 + x; // Reading x is ok x = 1;// A compilation time error.
There are two ways to initialize a final variable:
The following code shows how to defer final variable initialization until a later time.
final int multiplier; // A blank final variable // Set the value of multiplier first time multiplier = 3; // Ok to read the multiplier variable int value = 100 * multiplier;