1.11.2 Finality

A Java class definition, method definition, field definition, method parameter, or local variable may be preceded by the keyword final. This modifier has a slightly different meaning in each of these four contexts:

1.

a final class cannot be extended;

2.

a final method cannot be overridden;

3.

a final field cannot be modified once it is initialized; and

4.

a final parameter cannot be modified.

As long as Java programs are written in a functional style, every field and every parameter can be marked final without adversely affecting program compilation or execution. Henceforth, we recommend this practice.