♯OOP: Polymorphism (Definitions)

"Literally, from the Greek for many forms, and refers to the ability of different objects to respond differently to the same commands." (Greg Perry, "Sams Teach Yourself Beginning Programming in 24 Hours" 2nd Ed., 2001)

"The ability to treat many sub-types as if they were of the same base type." (Jesse Liberty, "Sams Teach Yourself C++ in 24 Hours" 3rd Ed., 2001)

"The capability of objects from different classes to accept the same message." (Stephen G Kochan, "Programming in Objective-C", 2003)

"The concept that two or more classes of objects can respond to the same message in different ways, using polymorphic operations. Also, the ability to define polymorphic operations." (Craig Larman, "Applying UML and Patterns", 2004)

"In object-oriented design, the principle that the same definition can be used with different types of data (specifically, different class implementations), resulting in more general and abstract implementations." (David C Hay, "Data Model Patterns: A Metadata Map", 2010)

"The redefinition of the body of a superclass method inherited by a subclass. The polymorphic method retains the same signature." (Jan L Harrington, "SQL Clearly Explained" 3rd Ed., 2010)

"The ability of a piece of code to work with more than one type." (Mark C Lewis, "Introduction to the Art of Programming Using Scala", 2012)

"The notion that you can tell an object to do something generic, and the object will interpret the command in different ways depending on its type." (Jon Orwant et al, "Programming Perl, 4th Ed.", 2012)

"The ability of a language to determine at runtime which of several possible methods will be executed for a given invocation" (Nell Dale & John Lewis, "Computer Science Illuminated" 6th Ed., 2015)

"The ability to treat a child object as if it were actually from a parent class. For example, it lets you treat a Student object as if it were a Person object because a Student is a type of Person." (Rod Stephens, "Beginning Software Engineering", 2015)

"Two objects can receive the same input and have different outputs." (Adam Gordon, "Official (ISC)2 Guide to the CISSP CBK" 4th Ed., 2015)

"The ability of an object variable to reference objects of different classes at different times during the execution of a program" (Nell Dale et al, "Object-Oriented Data Structures Using Java" 4th Ed., 2016)

"One of the fundamental principles of an object-oriented language. Polymorphism states that a type that extends another type is a “kind of” the parent type and can be used interchangeably with the original type by augmenting or refining its capabilities." (Daniel Leuck et al, "Learning Java" 5th Ed., 2020)

🧿Albert Einstein - Collected Quotes

“As soon as science has emerged from its initial stages, theoretical advances are no longer achieved merely by a process of arrangement. Guided by empirical data, the investigator rather develops a system of thought which, in general, is built up logically from a small number of fundamental assumptions, the so-called axioms. We call such a system of thought a theory. The theory finds the justification for its existence in the fact that it correlates a large number of single observations, and it is just here that the 'truth' of the theory lies. “ (Albert Einstein: “Relativity: The Special and General Theory”, 1916)

“No fairer destiny could be allotted to any physical theory, than that it should of itself point out the way to the introduction of a more comprehensive theory, in which it lives on as a limiting case.” (Albert Einstein: “Relativity, The Special and General Theory”, 1916)

“It can scarcely be denied that the supreme goal of all theory is to make the irreducible basic elements as simple and as few as possible without having to surrender the adequate representation of a single datum of experience.” (Albert Einstein, [lecture] 1933)

"Most of the fundamental ideas of science are essentially simple, and may, as a rule, be expressed in a language comprehensible to everyone."  (Albert Einstein & Leopold Infeld, ”The Evolution of Physics”, 1938) 

"A theory is the more impressive the greater the simplicity of its premises is, the more different kinds of things it relates, and the more extended its area of applicability." (Albert Einstein, "Autobiographical Notes", 1949)

“The mere formulation of a problem is often far more essential than its solution. To raise new questions, new possibilities, to regard old problems from a new angle, requires creative imagination and marks real advances in science.” (Albert Einstein)

"To raise new questions, new possibilities, to regard old problems from a new angle, requires creative imagination and marks real advance in science." (Albert Einstein)

“We can not solve our problems with the same level of thinking that created them.” (Albert Einstein)

OOP: Abstraction (Definitions)

"A view of a problem that extracts the essential information relevant to a particular purpose and ignores the remainder of the information." (IEEE, 1983)

"[A] simplified description, or specification, of a system that emphasizes some of the system's details or properties while suppressing others. A good abstraction is one that emphasizes details that are significant to the reader or user and suppress details that are, at least for the moment, immaterial or diversionary." (M Shaw, Abstraction Techniques in Modern Programming Languages", IEEE Software Vol. 1 (4), 1984)

"[abstraction:] (1) A view of an object that focuses on the information relevant to a particular purpose and ignores the remainder of the information.(2) The process of formulating a view as in (1)."(IEEE," IEEE Standard Glossary of Software Engineering Terminology", 1990)  

"[data abstraction:] (1) The process of extracting the essential characteristics of data by defining data types and their associated functional characteristics and disregardng representation details. (2) The result of the process in (1)." (IEEE," IEEE Standard Glossary of Software Engineering Terminology", 1990) 

"Abstraction is a process whereby we identify the important aspects of a phenomenon and ignore its details." (Ghezzi et al, Fundamentals of Software Engineering, 1991)

"Abstraction is generally defined as 'the process of formulating generalised concepts by extracting common qualities from specific examples.'" (Blair et al, "Object-Oriented Languages, Systems and Applications", 1991)

"An abstraction denotes the essential characteristics of an object that distinguish it from all other kinds of object and thus provide crisply defined conceptual boundaries, relative to the perspective of the viewer." (Grady Booch, Object-Oriented Design With Applications, 1991)

"The act of concentrating the essential or general qualities of similar things. Also, the resulting essential characteristics of a thing." (Craig Larman, "Applying UML and Patterns: An Introduction to Object-Oriented Analysis and Design and the Unified Process", 1997)

"Abstraction is the purposeful suppression, or hiding, of some details of a process or artifact, in order to bring out more clearly other aspects, details, or structure." (Timothy Budd, "An Introduction to Object-Oriented Programming" 3rd Ed., 2002)

"Abstraction can have several meanings depending on the context. In software, it often means combining a set of small operations or data items and giving them a name. For example, control abstraction takes a group of operations, combines them into a procedure, and gives the procedure a name. As another example, a class in object-oriented programming is an abstraction of both data and control. More generally, an abstraction is a representation that captures the essential character of an entity, but hides the specific details. Often we will talk about a named abstraction without concern for the actual details, which may not be determined." (Beverly A Sanders, "Patterns for Parallel Programming", 2004)

"Abstraction, as a process, denotes the extracting of the essential details about an item, or a group of items, while ignoring the inessential details. Abstraction, as an entity, denotes a model, a view, or some other focused representation for an actual item." (Edward V Berard, "Abstraction, Encapsulation, and Information Hiding", cca. 2006)

"The idea of minimizing the complexity of something by hiding the details and just providing the relevant information. It’s about providing a high-level specification rather than going into lots of detail about how something works. In the cloud, for instance, in an IaaS delivery model, the infrastructure is abstracted from the user." (Marcia Kaufman et al, "Big Data For Dummies", 2013)

"Minimizing the complexity of something by hiding the details and just providing the relevant information. It’s about providing a high-level specification rather than going into a lot of detail about how something works. In the cloud, for instance, in an IaaS delivery model, the infrastructure is abstracted from the user." (Judith S Hurwitz, "Cognitive Computing and Big Data Analytics", 2015)

"A model of a complex system that includes only the details essential to the viewer" (Nell Dale & John Lewis, "Computer Science Illuminated, 6th Ed.", 2015)

"The capability to suppress unnecessary details so the important, inherent properties can be examined and reviewed." (Adam Gordon, "Official (ISC)2 Guide to the CISSP CBK" 4th Ed., 2015)

"A model of a system that includes only the details essential to the perspective of the viewer of the system" (Nell Dale et al, "Object-Oriented Data Structures Using Java" 4th Ed., 2016)

"Way of expressing an idea in a specific context while at the same time suppressing details irrelevant in that context." (Karl Beecher, "Computational Thinking - A beginner's guide to problem-solving and programming", 2017)

"The act of representing essential features while hiding the details to reduce complexity." (O Sami Saydjari, "Engineering Trustworthy Systems: Get Cybersecurity Design Right the First Time", 2018)

"The deliberate reduction in dependency between a component and other components it works with is a way to make the component generally more useful." (Judith Hurwitz et al, "Service Oriented Architecture For Dummies" 2nd Ed., 2009)

OOP: Visibility (Definitions)

[COM Visibility:] "Indicates whether a .NET type or member is accessible from COM. Anything public in .NET is visible to COM unless it’s marked with the ComVisibleAttribute custom attribute with its argument set to false, or its containing assembly is marked with the attribute with its argument set to false." (Adam Nathan, ".NET and COM: The Complete Interoperability Guide", 2002)

"The level of access granted to other classes or variables. Indicates whether something can be 'seen' from a location in a program." (Marcus Green & Bill Brogden, "Java 2™ Programmer Exam Cram™ 2 (Exam CX-310-035)", 2003)

"The ability to see or have reference to an object." (Craig Larman, "Applying UML and Patterns", 2004)

"Ability to enforce fine-grained access to and operations on data at the record, attribute, and attribute-value levels based on user entitlements and data usage and access policies." (Alex Berson & Lawrence Dubov, "Master Data Management and Data Governance", 2010)

"An attribute of operation in object-oriented design that tells whether the operation can be 'seen' by any program, or whether it is 'private' - only accessible within the model involved." (David C Hay, "Data Model Patterns: A Metadata Map", 2010)

"The scope in which a declared type or type member is visible to other types and members." (Dean Wampler, "Functional Programming for Java Developers", 2011)

♯OOP: Encapsulation (Definitions)

"It is a simple, yet reasonable effective, system-building tool. It allows suppliers to present cleanly specified interfaces around the services they provide. A consumer has full visibility to the procedures offered by an object, and no visibility to its data. From a consumer's point of view, and object is a seamless capsule that offers a number of services, with no visibility as to how these services are implemented [...] technical term for this is encapsulation." (Brad J Cox, "Object Oriented Programming: An Evolutionary Approach", 1986)

A software development technique that consists of isolating a system function or a set of data and operations on those data within a module and providing precise specifications for the module. (IEEE," IEEE Standard Glossary of Software Engineering Terminology", 1990)

"The concept of encapsulation as used in an object-oriented context is not essentially different from its dictionary definition. It still refers to building a capsule, in the case a conceptual barrier, around some collection of things." (Rebecca Wirfs-Brock et al, "Designing Object-Oriented Software", 1990]

"Encapsulation or equivalently information hiding refers to the practice of including within an object everything it needs, and furthermore doing this in such a way that no other object need ever be aware of this internal structure." (Ian Graham, "Object-Oriented Methods", 1991]

"Data hiding is sometimes called encapsulation because the data and its code are put together in a package or 'capsule.'" (David N Smith, "Concepts of Object-Oriented Programming", 1991)

"Encapsulation is used as a generic term for techniques which realize data abstraction. Encapsulation therefore implies the provision of mechanisms to support both modularity and information hiding. There is therefore a one to one correspondence in this case between the technique of encapsulation and the principle of data abstraction." (Gordon Blair et al, "Object-Oriented Languages, Systems and Applications", 1991)

"Encapsulation (also information hiding) consists of separating the external aspects of an object which are accessible to other objects, from the internal implementation details of the object, which are hidden from other objects." (James Rumbaugh et al, "Object-Oriented Modeling and Design", 1991)

"[...] encapsulation - also known as information hiding - prevents clients from seeing its inside view, were the behavior of the abstraction is implemented." (Grady Booch, "Object-Oriented Design With Applications", 1991)

"We say that the changeable, hidden information becomes the secret of the module; also, according to a widely used jargon, we say that such information is encapsulated within the implementation." (Carlo Ghezzi et al, "Fundamentals of Software Engineering", 1991]

"As a process, encapsulation means the act of enclosing one or more items within a (physical or logical) container. Encapsulation, as an entity, refers to a package or an enclosure that holds (contains, encloses) one or more items. It is extremely important to note that nothing is said about 'the walls of the enclosure'. Specifically, they may be 'transparent', 'translucent', or even 'opaque'." Compare with information hiding, which implies invisibility." (Bill Pribyl & Steven Feuerstein, "Learning Oracle PL/SQL", 2001)

"Encasing information and behavior within an object so that its structure and implementation are hidden to other objects that interact with it." (Marcus Green & Bill Brogden, "Java 2 Programmer Exam Cram 2 (Exam CX-310-035)", 2003)

"A mechanism used to hide the data, internal structure, and implementation details of some element, such as an object or subsystem. All interaction with an object is through a public interface of operations." (Craig Larman, "Applying UML and Patterns", 2004)

"An object-oriented technique that may hide, or abstract, the inner workings of an object and expose only the relevant characteristics and operations on the object to other objects." (Bob Bryla, "Oracle Database Foundations", 2004)

"Restricting the visibility of members of a type so they are not visible to clients of the type when they shouldn’t be. This is a way of exposing only the abstraction supported by the type, while hiding implementation details, which prevents unwanted access to them from clients and keeps the abstraction exposed by the type consistent and minimal." (Dean Wampler & Alex Payne, "Programming Scala", 2009)

"In object-oriented design, the principle that it should be possible to refer to an object with behavior and not know anything about how that behavior is implemented." (David C Hay, "Data Model Patterns: A Metadata Map", 2010)

"Detail hiding. A class hides its internal details so the rest of the program doesn't need to understand how they work, just how to use them." (Rod Stephens, "Stephens' Visual Basic® Programming 24-Hour Trainer", 2011)

"(1) A language mechanism for restricting access to some of an object’s components. (2) A language construct that facilitates the bundling of data with methods (or other functions) operating on that data." (Craig S Mullins, "Database Administration: The Complete Guide to DBA Practices and Procedures", 2012)

"The veil of abstraction separating the interface from the implementation (whether enforced or not), which mandates that all access to an object’s state be through methods alone." (Jon Orwant et al, "Programming Perl" 4th Ed., 2012)

"A language feature that enforces information hiding; bundling data and actions so that the logical properties of data and actions are separated from the implementation details" (Nell Dale & John Lewis, "Computer Science Illuminated" 6th Ed., 2015)

"The bundling of data with the procedures that operate on that data, such that data may only be changed by those procedures - a technique for reducing program complexity." (O Sami Saydjari, "Engineering Trustworthy Systems", 2018)

"The object-oriented programming technique of limiting the exposure of variables and methods to simplify the API of a class or package. Using the private and protected keywords, a programmer can limit the exposure of internal ('black box') parts of a class. Encapsulation reduces bugs and promotes reusability and modularity of classes. This technique is also known as data hiding." (Daniel Leuck et al, "Learning Java" 5th Ed., 2020)

♯OOP: Inheritance (Definitions)

"Creating a new type that can extend the characteristics of an existing type." (Jesse Liberty, "Sams Teach Yourself C++ in 24 Hours" 3rd Ed., 2001)

"The ability of one data object to gain characteristics from another object." (Greg Perry, "Sams Teach Yourself Beginning Programming in 24 Hours" 2nd Ed., 2001)

"The process of passing methods and instance variables from a class, starting with the root object down to subclasses." (Stephen G Kochan, "Programming in Objective-C", 2003)

"A feature of object-oriented programming languages by which classes may be specialized from more general superclasses. Attributes and method definitions from superclasses are automatically acquired by the subclass." (Craig Larman, "Applying UML and Patterns", 2004)

"Acquiring the properties of the parent, or base object, in a new object." (Bob Bryla, "Oracle Database Foundations", 2004)

"The ability of a class to inherit features from another class via the < operator. See multiple inheritance, single inheritance." (Michael Fitzgerald, "Learning Ruby", 2007)

"A strong relationship between one class or trait and another class or trait. The inheriting (derived) class or trait incorporates the members of the parent class or trait, as if they were defined within the derivative. The derivative may override inherited members (in most cases). Instances of a derivative are substitutable for instances of the parent." (Dean Wampler & Alex Payne, "Programming Scala", 2009)

"A general to specific relationship between classes in an object-oriented environment." (Jan L Harrington, "SQL Clearly Explained 3rd Ed. ", 2010)

"A strong coupling between one class or interface and another. The inheriting (derived) class or interface incorporates the members of the parent class or interface, as if they were defined within the derivative. Hence, inheritance is a form of reuse. The derivative may override inherited members (unless declared final). For a properly defined derived type, instances of it are substitutable for instances of the parent, satisfying the Liskov Substitution Principle." (Dean Wampler, "Functional Programming for Java Developers", 2011)

"The process of passing methods and instance variables from a class, starting with the root object, down to subclasses." (Stephen G Kochan, "Programming in Objective-C" 4th Ed., 2011)

"What you get from your ancestors, genetically or otherwise. If you happen to be a class, your ancestors are called base classes and your descendants are called derived classes. See single inheritance and multiple inheritance." (Jon Orwant et al, "Programming Perl" 4th Ed., 2012)

"Building a class from the basic functionality of an existing class and then adding new functions." (Matt Telles, "Beginning Programming", 2014)

"A mechanism by which one class acquires the properties - data fields and methods - of another class" (Nell Dale & John Lewis, "Computer Science Illuminated" 6th Ed., 2015)

"An important feature of object-oriented programming that involves defining a new object by changing or refining the behavior of an existing object. Through inheritance, an object implicitly contains all of the non-private variables and methods of its superclass. Java supports single inheritance of classes and multiple inheritance of interfaces." (Daniel Leuck et al, "Learning Java" 5th Ed., 2020)

🧿Steve Jobs - Collected Quotes

"Computers are the first thing to come along since books that will sit there and interact with you endlessly, without judgment." (Steve Jobs, Playboy, 1985)

"You can’t just ask customers what they want and then try to give that to them. By the time you get it built, they’ll want something new." (Steve Jobs, 1989)

"What a computer is to me is the most remarkable tool that we have ever come up with. It’s the equivalent of a bicycle for our minds." (Steve Jobs, "Memory and Imagination: New Pathways to the Library of Congress", 1991)

"Technology is nothing. What’s important is that you have a faith in people, that they’re basically good and smart, and if you give them tools, they’ll do wonderful things with them." (Steve Jobs, Rolling Stone, 1994)

"You can’t really predict exactly what will happen, but you can feel the direction that we’re going. And that’s about as close as you can get. Then you just stand back and get out of the way, and these things take on a life of their own." (Steve Jobs, Rolling Stone, 1994)

"For me, the most exciting thing in the software area is the Internet, and part of the reason for that is no one owns it. It’s a free for all, it’s much like the early days of the personal computer." (Steve Jobs, Wall $treet Week, 1995)

"Creativity is just connecting things. When you ask creative people how they did something, they feel a little guilty because they didn’t really do it, they just saw something. It seemed obvious to them after a while. That’s because they were able to connect experiences they’ve had and synthesize new things." (Steve Jobs, 1996)

"The Web is not going to change the world, certainly not in the next 10 years. It’s going to augment the world." (Steve Jobs, Wired, 1996)

"It’s really hard to design products by focus groups. A lot of times, people don’t know what they want until you show it to them." (Steve Jobs, BusinessWeek, 1998)

"That’s been one of my mantras - focus and simplicity. Simple can be harder than complex: You have to work hard to get your thinking clean to make it simple. But it’s worth it in the end because once you get there, you can move mountains." (Steve Jobs, Business Week, 1998)

"The problem with the Internet startup craze isn’t that too many people are starting companies; it’s that too many people aren’t sticking with it. That’s somewhat understandable, because there are many moments that are filled with despair and agony, when you have to fire people and cancel things and deal with very difficult situations. That’s when you find out who you are and what your values are." (Steve Jobs, Fortune, 2000)

"Process makes you more efficient." (Steve Jobs, BusinessWeek, 2004)

"To turn really interesting ideas and fledgling technologies into a company that can continue to innovate for years, it requires a lot of disciplines."  (Steve Jobs, BusinessWeek, 2004)

"You need a very product-oriented culture, even in a technology company. Lots of companies have tons of great engineers and smart people. But ultimately, there needs to be some gravitational force that pulls it all together. Otherwise, you can get great pieces of technology all floating around the universe." (Steve Jobs, Newsweek, 2004)

"Things don’t have to change the world to be important." (Steve Jobs, Wired, 2006)

"Sometimes when you innovate, you make mistakes. It is best to admit them quickly, and get on with improving your other innovations." (Steve Jobs)

"The broader one’s understanding of the human experience, the better design we will have." (Steve Jobs)

♯OOP: Function (Definitions)

"(1) A defined objective or characteristic action of a system or component. For example, a system may have inventory control as its primary function. (2) A software module that performs a specific action, is invoked by the appearance of its name in an expression, may receive input values, and returns a single value." (IEEE," IEEE Standard Glossary of Software Engineering Terminology", 1990) 

"A set of instructions that operates as a single logical unit, can be called by name, accepts input parameters, and returns information. In programming languages such as C, a function is a named subroutine of a program that encapsulates some logic. The function can be called by name, using parameters to pass data into the function and retrieve data produced by the function." (Microsoft Corporation, "SQL Server 7.0 System Administration Training Kit", 1999)

"A block of code that performs a service, such as adding two numbers or printing to the screen." (Jesse Liberty, "Sams Teach Yourself C++ in 24 Hours" 3rd Ed., 2001)

"A program that returns a value to the program or environment from which it is called." (Bill Pribyl & Steven Feuerstein, "Learning Oracle PL/SQL", 2001)

"A routine that processes data inside a program." (Greg Perry, "Sams Teach Yourself Beginning Programming in 24 Hours" 2nd Ed., 2001)

"A block of statements identified by a name that can accept one or more arguments passed to it by value and can optionally return a value. Functions can be local (static) to the file in which they're defined or global, in which case they can be called from functions or methods defined in other files." (Stephen G Kochan, "Programming in Objective-C", 2003)

"A named set of predefined programming language commands that performs a specific task given zero, one, or more arguments and returns a value." (Bob Bryla, "Oracle Database Foundations", 2004)

"A piece of code that operates as a single logical unit. A function is called by name, accepts optional input parameters, and returns a status and optional output parameters. Many programming languages support functions, including C, Visual Basic, and Transact-SQL. Transact-SQL supplies built-in functions, which cannot be modified, and supports user-defined functions, which can be created and modified by users." (Jim Joseph, "Microsoft SQL Server 2008 Reporting Services Unleashed", 2009)

"A block of statements identified by a name that can accept one or more arguments passed to it by value and can optionally return a value. Functions can be either local (static) to the file in which they’re defined or global, in which case they can be called from functions or methods defined in other files." (Stephen G Kochan, "Programming in Objective-C" 4th Ed., 2011)

"A packaged set of code that other pieces of code can invoke and that returns a result value." (Rod Stephens, "Stephens' Visual Basic Programming 24-Hour Trainer", 2011)

"A single block of code that accomplishes a single task and can be reused." (Matt Telles, "Beginning Programming", 2014)