Using 'Final' keyword

A variable could be declared as final.  Doing so avoids its contents from being modified. Which means that you must initialize a final variable whenever its is declared. For instance

final int FILE_NEW = 1;

final int FILE_OPEN = 2;

final int FILE_SAVE = 3;

final int FILE_SAVEAS = 4;

final int FILE_QUIT = 5;

Following parts of your program could now use FILE_OPEN etc as if they were constants, without fear in which a value has been modified.

It is a general coding convention to select all uppercase identifiers for final variables. A Variable declared as final does not occupy memory on a per-instance basis. Therefore a final variable is essentially a constant.

The keyword final could also be applied to methods, but its meaning is substantially variant than when it is applied to variables. That second usage of final is defined in the further chapter, when inheritance is defined.