Understanding final keyword in Java

In Java, final keyword can be used with variable, method, class

final variable:

• we can not change value of final variable once it is initialized
• if final variable not initialized (blank final variable) at the time of declaration, it must be initialized in constructor
A static final variable that is not initialized during declaration can only be initialized in static block.

final method:

• final methods can not be overridden but methods can be inherited

final class:

• final class can not be inherited

Basic points to remember:

• All variables declared in interface are by default final
• constructor can not be declared final
• If method parameters are declared final then the value of these parameters cannot be changed
• Local final variable must be initialized during declaration