Objective 3)
Write code to construct instances of any concrete class including normal top level classes inner classes static inner classes and anonymous inner classes.
Inner Classes
· A class can be declared in any scope. Classes defined inside of other classes are known as nested classes. There are four categories of nested classes.
Top-level nested classes / interfaces
· Declared as a class member with static modifier.
· Just like other static features of a class. Can be accessed / instantiated without an instance of the outer class. Can access only static members of outer class. Can’t access non-static instance variables or methods.
· Very much like any-other package level class / interface. Provide an extension to packaging by the modified naming scheme at the top level.
· Classes can declare both static and non-static members.
· Any accessibility modifier can be specified.
· Nested interfaces are implicitly static (static modifier also can be specified). They can have any accessibility modifier. There are no non-static inner, local or anonymous interfaces.
Non-static inner classes
· Declared as a class member without static.
· An instance of a non-static inner class can exist only with an instance of its enclosing class. So it always has to be created within a context of an outer instance.
Outer.Inner i = new Outer().new Inner();
· Just like other non-static features of a class. Can access all the features (even private) of the enclosing outer class. Have an implicit reference to the enclosing instance.
· Cannot have any static members.
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