Programming

Active objects are one which instigate an interaction which owns a thread and they are responsible for handling control to other objects. In simple words it can be referred as client.

Passive objects are one, which passively waits for the message to be processed. It waits for another object that requires its services. In simple words it can be referred as server.

Persistent refers to an object’s ability to transcend time or space. A persistent object stores/saves its state in a permanent storage system with out losing the information represented by the object.

A non-persistent object is said to be transient or ephemeral. By default objects are considered as non-persistent.

Unified method is convergence of the Rumbaugh and Booch. Unified modeling lang. is the fusion of Rumbaugh, Booch and Jacobson as well as Betrand Meyer (whose contribution is “sequence diagram”). Its’ the superset of all the methodologies.

Even though Generalization satisfies Structural, Interface, Behaviour properties. It is mathematically very strong, as it is Antisymmetric and Transitive. Antisymmetric: employee is a person, but not all persons are employees. Mathematically all As’ are B, but all Bs’ not A.

If you look at the class representation of Rumbaugh and UML, It is some what similar and both are very easy to draw.

Software development method describes how to model and build software systems in a reliable and reproducible way. To put it simple, methods that are used to represent ones’ thinking using graphical notations.

Inner class in Programming:

classes defined in other classes, including those defined in methods are called inner classes. An inner class can have any accessibility including private.

Anonymous class in Programming:

Anonymous class is a class defined inside a method without a name and is instantiated and declared in the same place and cannot have explicit constructors.

Multithreading is the mechanism in which more than one thread run independent of each other within the process in any programming language such as C, C++, Java etc...

Overriding is used to redefines only the methods, but shadowing redefines the entire element.

Before 1994 there were different methodologies like Rumbaugh, Booch, Jacobson, Meyer etc who followed their own notations to model the systems.

The developers were in a dilemma to choose the method which best accomplishes their needs. This particular span was called as “method-wars”

The Three amigos namely,

James Rumbaugh (OMT): A veteran in analysis who came up with an idea about the objects and their Relationships (in particular Associations).

Grady Booch: A veteran in design who came up with an idea about partitioning of systems into subsystems.

Ivar Jacobson (Objectory): The father of USECASES, who described about the user and system interaction.

SBI stands for State, Behavior and Identity. Since every object has the above three.

State:

It is just a value to the attribute of an object at a particular time.

Behaviour:

It describes the actions and their reactions of that object.

Identity:

An object has an identity that characterizes its own existence. The identity makes it possible to distinguish any object in an unambiguous way, and independently from its state.

A class does not inherit constructors from any of its super classes.

Static modeling is used to specify structure of the objects that exist in the problem domain. These are expressed using class, object and USECASE diagrams. But Dynamic modeling refers representing the object interactions during runtime. It is represented by sequence, activity, collaboration and statechart diagrams

Downcasting concept is the casting from a general to a more specific type, i.e. casting down the hierarchy in programming.

No, method can not be overloaded because the methods can be called without using their return type in which case there is ambiguity for the compiler in programming languages.

A class that is declared without any access modifiers is said to have package access. This means that the class can only be accessed by other classes and interfaces that are defined within the same package.

1. In procedural program, programming logic follows certain procedures and the instructions are executed one after another. In OOP program, unit of program is object, which is nothing but combination of data and code.

2. In procedural program, data is exposed to the whole program whereas in OOPs program, it is accessible with in the object and which in turn assures the security of the code.

An argument can be passed in two ways in a programming language. They are Pass by Value and Passing by Reference.

Passing by value: This method copies the value of an argument into the formal parameter of the subroutine.

Passing by reference: In this method, a reference to an argument (not the value of the argument) is passed to the parameter.