Why use final in java?

Answer 1

The use of final denotes that a variable is a constant. For example:

final int PI = 3.14;

makes PI a constant. This is useful because now PI can't be changed, even accidentally, by you, the program, another programmer, or a user. Once a value is final, it is permanent, and can be used as a constant.

Note: usually programmers capitalize the names of constants, just to make it clear that the value is a constant.

Answer 2

They are unrelated. Static means that there is only one copy of the variable for the entire class - no matter how many objects you have. Final means the value can't change. A variable can be only static, only final, both, or none.

Answer 3

The final keyword can be used in many ways and has many uses in Java.

* A java variable that is declared with the keyword final can be assigned only once. They cannot be modified.

* A variable that is declared as final and not initialized is called a blank final variable. A blank final variable forces the constructors to initialize it. * Java classes declared as final cannot be extended. It cannot be inherited by any other class.

* Methods declared as final cannot be overridden in the sub classes.

* final parameters - values of the parameters cannot be changed after initialization. * Java local classes can only reference local variables and parameters that are declared as final. * A visible advantage of declaring a java variable as static final is, the compiled java class results in faster performance.

Answer 4

Final Variables

Declaring a variable with the final keyword makes it impossible to reassign a different value to that variable once it has been initialized with an explicit value (notice we said explicit rather than default). For primitives, this means that once the variable is assigned a value, the value can't be altered. For example, if you assign 10 to the int variable x, then x is going to stay 10, forever. That's pretty straightforward for primitives, but what does it mean to have a final object reference variable? A reference variable marked final can't ever be reassigned to refer to a different object. The data within the object can be modified, but the reference variable cannot be changed. In other words, if you have a final employee object variable, you can modify aspects of the employee but you cannot have the variable refer to say a manager.

Answer 5

Protected members can be accessed by classes that inherit from the class with the protected members. This allows direct access to that member for inheriting classes, without granting access to all classes (public).

This is often useful for utility methods that should be shared with inheriting classes, as well as variables that need to be accessed by inheriting classes.

As a brief example, a vehicle class with a private variable for the maximum number of passengers couldn't be extended to accommodate different maximum values (e.g. a car, truck, and airplane would all be forced to carry the same maximum number of passengers).

By making the variable protected, each subclass can specify their capacity without allowing outside classes the ability to specify the vehicle's capacity.

Answer 6

Finalize method is used to remove non-java resources

Answer 7

Final variables are stored in the same place all other variables are stored. "The JVM Heap"