Nested and Enum type in Java

1. Prepared Using
Nested Type
For Semester – III [MCA]
August
2012
Prepared by
Prof. Ashish Bhatia
ast.bhatia@gmail.com
ashish@asbspace.in
www.asbspace.in
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2. Note
● This ppt is for teaching purpose only.
● The ppt may contain some material from
books/api documentation/internet.
● No intention of breaking any rights or what so
ever.
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3. Nested Classes
● The class define inside another class are
known as Nested Class.
● Top Level Nested Class
● Inner class is static
● Inner Class
● Local Class
● Anonymous Class
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4. Why we need nested class?
● Logical Grouping of class
● Helper classes
● Increase encapuslation
●
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5. Top Level Nested Class
● Static member class is also known as top level
nested class.
● Member class and enclosing class shares trust
replationship in that they can access each
other memebers, including private members.
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7. Inner Classes
● Non-static member classes.
● Relationship :
● We cannot have an instance of innerclass without
having instance of the outer class.
● Used to represent one to many relationship.
● Eg : Account Class [Outer]and Transaction
class[Inner]
● We cannot have transaction without Account
● Inner class cannot have static members.
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9. Local Class
● Class inside a method, constructor or intializer
block.
● This class donot have access specifier and
cannot be dcelared static / non-static.
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11. Anonymous Class
● Do not have name.
● Defined and created at same place.
● Become part of expression.
● Single inheritance type either extend or
implement
● Always non-abstract.
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12. enum Type
● Java 5 onwards.
● Cannot have super class but can implement
interface.
● Number of instances are fixed.
● ; required after declaration.
● Sub class of Enum
● Instances have name and ordinal value.
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13. enum Type
●
Each instance are static and final.
●
Ordinal Value starts from 0
●
To access Month.January
●
Enum type are comparable [ ordinal]
●
Values and Valuesof
●
public static Month[] values()
●
public static Month valueOf(String n)
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