Static classes and final classes in java [duplicate]

Question

In Java (and in Android), what's the use of static class and final class declarations?

My question is not about static instances but class declarations like,

static class StaticClass {
    //variables and methods
}

and

final class FinalClass {
    //variables and methods
}

Thanks,

Answer 1

Static Nested Classes

As with class methods and variables, a static nested class is associated with its outer class. And like static class methods, a static nested class cannot refer directly to instance variables or methods defined in its enclosing class: it can use them only through an object reference. Note: A static nested class interacts with the instance members of its outer class (and other classes) just like any other top-level class. In effect, a static nested class is behaviorally a top-level class that has been nested in another top-level class for packaging convenience.

Static nested classes are accessed using the enclosing class name:

OuterClass.StaticNestedClass

For example, to create an object for the static nested class, use this syntax:

OuterClass.StaticNestedClass nestedObject =
     new OuterClass.StaticNestedClass();

http://docs.oracle.com/javase/tutorial/java/javaOO/nested.html

Final Classes

A class that is declared final cannot be subclassed. This is particularly useful, for example, when creating an immutable class like the String class.

http://docs.oracle.com/javase/tutorial/java/IandI/final.html

Answer 2

final classes will restrict for further extends (Inherit).

You can not use static keyword on outer class,static is permitted only to inner classes Static classes