The document discusses criticisms and insights regarding object-oriented programming (OOP), featuring quotes from notable figures in the field. It highlights various aspects of OOP including classes, objects, inheritance, and methods, alongside contrasting opinions on its effectiveness. The text also references trends and definitions while indicating a debate between OOP and functional programming.

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Yegor Bugayenko
What’s Wrong With
Object-Oriented Programming

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takes.org
eolang.org
“Elegant Objects”

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“Java is the most distressing
thing to happen to computing
since MS-DOS.”
—Alan Kay, 1997

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“Object-oriented programming
offers a sustainable way to
write spaghetti code.”
—Paul Graham, 2003

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“OO seems to bring at least as
many problems to the table as
it solves.”
—Jeff Atwood, 2007

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Google Trends, May 2017
“OOP (blue) vs FP (red)”
https://goo.gl/Ezmma8

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“Objects are not data
structures.”
—Robert Martin, 2014
https://goo.gl/qmRFH4

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—page 98
“A class is a collection of
data fields that hold values
and methods that operate
on those values”

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—page 40
“An object is some memory
that holds a value of some
type.”

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“An object consists of some
private memory and a set of
operations.”
—page 6

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Theory Practicevs.

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Getters & Setters
1

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public class Book {
private String title;
public void setTitle(String t) {
this.title = t;
}
public String getTitle() {
return this.title;
}
}

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Static Methods
2

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public class BookUtils {
public static void print(Book b) {
System.out.println(
“The title is: ” + b.getTitle()
);
}
}

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NULL
3

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Book b = library.find(“UML Distilled”);
if (b == null) {
// The book not found
} else {
System.out.println(
“This is the book: ” + b
);
}

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Reflection
4

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Book b = library.find(“UML Distilled”);
if (b instanceof Ebook) {
String pdf = Ebook.class.cast(b).getPDF();
}

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Inheritance
5

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pubic class Manuscript {
protected String title;
public String html() {
return “<h1>” + this.title + “</h1>”;
}
}
pubic class Book extends Manuscript {
protected String title;
public void rename(String t) {
this.title = t;
}
}

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Annotations
6

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Book b = new Book();
String xml = m.marshall(b);
@XmlRoot
class Book {
@XmlElement
private String title;
}

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“I invented the term object-
oriented, and I can tell you I
did not have C++ in mind.”
—Alan Kay, 1997

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The article on the blog: