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In general we can not CREATE object for a private class, but we can ACCESS STATIC method of a private class so call that method using its class name and IMPORT that object.

For example take one static method with an exporting parameter inside private class and WRITE object creation code in that static method and export that object.

In general we can not create object for a private class, but we can access static method of a private class so call that method using its class name and import that object.

For example take one static method with an exporting parameter inside private class and write object creation code in that static method and export that object.

class <cl_name> definition.
Public section.
Methods: m1 IMPORTING p1 TYPE <c>
Exporting p2 type <i>
Changing p3 type <n>
RETURNING p4 type <i>
Exceptions <e1>.
Protected section.
Private section.
Endclass.
Class <c1_name> implementation.
Method m1.­­­­­­
Endmethod.
Endclass

class <cl_name> definition.
Public section.
Methods: m1 importing p1 type <c>
Exporting p2 type <i>
Changing p3 type <n>
Returning p4 type <i>
Exceptions <e1>.
Protected section.
Private section.
Endclass.
Class <c1_name> implementation.
Method m1.­­­­­­
Endmethod.
Endclass

• PUBLIC class
• Private class
• FINAL class
• Single­ton class
• ABSTRACT class
• PERSISTENT class
• Friend class

We can create MANY instances of the same CLASS with in a PROGRAM, but we cannot create many instances of FUNCTION group.

We can create many instances of the same class with in a program, but we cannot create many instances of function group.

• Local classes are defined LOCALLY with in a PROGRAM and the other programs can’t access the same classes directly.
• But global classes are not like that they are globally ACCESSIBLE from ABAP environment.
• Global classes are centrally defined in a repository. Transaction CODE for global classes is SE24(CLASS builder).

CALL METHOD ref­&GT;method_name .

Call method ref­>method_name .

DATA: REF TYPE ref to .
CREATE OBJECT ref.

Data: ref type ref to .
Create object ref.

With TCODE SE24.

With tcode SE24.

It just like a self­reference, by this we can call methods that are with in same CLASS with out CREATING OBJECT.

It just like a self­reference, by this we can call methods that are with in same class with out creating object.

FRIEND class is a class it can ACCESS PRIVATE components of it’s FRIENDS class.

Friend class is a class it can access private components of it’s friends class.

 YES, CLASS can be created without any CONSTRUCTOR. Default constructor will be created when we define a class without constructor.

 Yes, class can be created without any constructor. Default constructor will be created when we define a class without constructor.

Polymorphism is a concept by which the same METHOD NAMES will behave differently in different classes i.e each method will have it's own IMPLEMENTATION in different classes but with the same NAME.

Polymorphism is a concept by which the same method names will behave differently in different classes i.e each method will have it's own implementation in different classes but with the same name.

CONSTRUCTOR's are special type of METHODS, constructor method is EXECUTED automatically whenever a object is created or instantiated.

• Constructor: This method is executed automatically whenever object is created, this is used to set DEFAULT values with respect to instance/object. The NAME of the constructor method is CONSTRUCTOR.
• Static Constructor: This method is executed automatically whenever object is created, this is used to set default values globally irrespective of instances/objects.The name of the static constructor is CLASS_ CONSTRUCTOR.

CONSTRUCTOR's are special type of methods, constructor method is executed automatically whenever a object is created or instantiated.

Some of the main advantages of Object Oriented ALV

• We have no of events AVAILABLE in the classes when compared to ALV with function modules which gives flexibility for the programmer to develop ALV'S for various scenarios.
• We can display more than one ALV grid data on a single screen.
• The ALV grid data is displayed in the form of custom CONTAINER with which we can control the size of ALV grid Whereas we cannot control the size of the ALV with function Modules.
• We can also place DIFFERENT UI elements LIKE checkbox, RADIOBUTTON on the same screen in addition ALV grid data.

Some of the main advantages of Object Oriented ALV

It is the keyword which INDICATES the CLASS definition is delayed or POSTPONED or Defined at some place in PROGRAM.

Syntax : CLASSÂ Â DEFINITION DEFERED.

It is the keyword which indicates the class definition is delayed or postponed or Defined at some place in program.

Syntax : CLASSÂ Â DEFINITION DEFERED.

• we cannot create an object to the abstract class INSTEAD create an object to the CHILD class and call the methods .
• Abstract class are mainly USED for creating INHERITANCE.

• It is a class which CONTAINS methods with IMPLEMENTATION as well as methods WITHOUT implementation .
• ABSTRACT class is a class which contains at least ONE abstract method.

ABSTRACT METHODS is a METHOD which doesn't CONTAIN any IMPLEMENTATION.

Abstract methods is a method which doesn't contain any implementation.

• These are special type of methods
• CONSTRUCTOR method is executed automatically WHENEVER a OBJECT is CREATED or INSTANTIATED
• These methods are mainly used to set default values in a class
• The name of the constructor method is 'constructor'
• These methods have only importing parameters
• There are no exporting parameters

We need to follow below steps when working with events in Object Oriented ABAP:

• Define an event
• Define a method
• Link event and method and convert the method into event-handler method
• CREATE a triggering method which will raise the event
• USE SET handler and REGISTER event handler method to a PARTICULAR instance in the program

We need to follow below steps when working with events in Object Oriented ABAP:

EVENT is a MECHANISM by which method of one class can RAISE method of ANOTHER class, without the HAZARD of instantiating that class.

Event is a mechanism by which method of one class can raise method of another class, without the hazard of instantiating that class.

LOCAL CLASSES are DEFINED in an ABAP PROGRAM (Transaction SE38) and can only be USED in the program in which they are defined.

Local classes are defined in an ABAP program (Transaction SE38) and can only be used in the program in which they are defined.

Global classes and interfaces are DEFINED in the Class Builder (TRANSACTION SE24) in the ABAP Workbench.All of the ABAP programs in an R/3 SYSTEM can ACCESS the global classes

Global classes and interfaces are defined in the Class Builder (Transaction SE24) in the ABAP Workbench.All of the ABAP programs in an R/3 System can access the global classes

SINGLETON CLASS is a class which allows to instantiate(Create OBJECT) only once .

Singleton class is a class which allows to instantiate(Create Object) only once .

Yes, we can declare events in INTERFACE in OBJECT Oriented ABAP

Yes, we can declare events in interface in Object Oriented ABAP

No we can not make interface METHODS as ABSTRACT or final in OBJECT ORIENTED ABAP

No we can not make interface methods as abstract or final in Object Oriented ABAP

Before going to static classes, you should understand static COMPONENTS.

• Static Components: Static components (static attributes, static events and static methods) exists GLOBALLY, no need to create object/INSTANCE of the class to access them, we can access them by using static component selector => .
• Static Class: A class that only CONTAINS static components and no instance components is REFERRED to as a static class.
• Singleton Class: It is a class which does not allow you to create multiple instances.

Before going to static classes, you should understand static components.

CLASS is USER DEFINED data type which CONTAINS methods, EVENTS, attributes, interfaces etc.

Class is user defined data type which contains methods, events, attributes, interfaces etc.

INSTANCE METHOD is AVAILABLE separately in each object (instance), static method is global and no instance is required for static method.

Instance method is available separately in each object (instance), static method is global and no instance is required for static method.

PUBLIC attributes can be ACCESSED by class, subclasses and other classes where as PRIVATE attributes can be accessed by class itself only.

Public attributes can be accessed by class, subclasses and other classes where as Private attributes can be accessed by class itself only.

Single-ton CLASS is a class which ALLOWS to INSTANTIATE once only .

Single-ton class is a class which allows to instantiate once only .

No, you can not RAISE EVENTS in interface, Because there is no Implementation for the methods. We can CREATE events in INTERFACES .

No, you can not raise events in interface, Because there is no Implementation for the methods. We can create events in interfaces .

ALIAS is an alias NAME for the INTERFACE METHOD IMPLEMENTED in the class .

Alias is an alias name for the interface method implemented in the class .

Yes, by USING INTERFACE CONCEPT in SAP ABAP, we can polymorphism

Yes, by using interface concept in SAP ABAP, we can polymorphism

Yes, by USING INTERFACE concept in SAP ABAp, we can ACHIEVE multiple inheritance

Yes, by using interface concept in SAP ABAp, we can achieve multiple inheritance

No, we can not INSTANTIATE INTERFACE using create OBJECT keyword.

No, we can not instantiate interface using create object keyword.

Interface is CLASS which CONTAINS methods without IMPLEMENTATIONS.

Interface is class which contains methods without implementations.

No it is not MANDATORY to IMPLEMENT all normal INTERFACE METHODS but it is mandatory to implement all ABSTRACT methods.

No it is not mandatory to implement all normal interface methods but it is mandatory to implement all Abstract methods.