Object-oriented programming concepts were developed in the 1960s with languages like Simula. Java was created in the 1990s and was intended for embedded systems, requiring small size and reliability. Java programs are compiled to bytecode, allowing cross-platform portability. Key features of Java include being simple, object-oriented, network-capable, interpreted yet high-performance, robust with exception handling and memory management, secure, architecture neutral, portable, multithreaded, and dynamic.

1. A Brief History of Object-Oriented
Programming
Object-Oriented Programming

2. Outline
 A Brief History Object-Oriented Programming
 The History of Java
 Client-Side Computing
• Bytecode Interpreters and Just-In-Time Compilers
• Security Issues
• Specialization of Interfaces
 The White Paper Description
• Java Is Simple
• Java Is Object-Oriented
• Java Is Network Savvy
• Java Is Interpreted
• Java Is Robust

3. Outline
• Java Is Secure
• Java Is Architecture Neutral
• Java Is Portable
• Java Is High-Performance
• Java Is Multithreaded
• Java Is Dynamic

4. A Brief History Object-Oriented
Programming
 All the major concepts were developed in the 1960s as part
of a language called Simula
 Alan Kay and his group developed a programming
language named Smalltalk in the 1970s
 Bjarne Stroustrup developed an extension to the C
language that eventually evolved to the language C++
 Explosion of the research in object-oriented programming
techniques began
 In the first major conference on object-oriented
programming, in 1986, there were dozens of languages
 These included Eiffel, Objective-C, Actor, Object Pascal,
and various Lisp dialects
 Object-oriented programming became mainstream

5. The History of Java
 Originally names as Oak and was developed in 1991 by
James Gosling.
 Intended as a language for use in embedded customer
electronic applications
 This determined the characteristics of the language
 Two of the most important features size and reliability
 Processors in embedded systems are very small, possessing
small memory, thus the language must be able to translate
into very concise encoding
 Embedded systems should almost never fail and should
respond to exceptional and erroneous conditions

6. Client-Side Computing
 Internet a classic example of a client/server system
 A person working at own computer is a client
 The client application communicates over the Internet with
another computer, server
 Dynamic behavior by executing programs
 In the past programs executed on the server
 The key idea in client-side is that the server transmits the
program to the client to execute locally

7. Bytecode Interpreters and Just-In-Time
Compilers
 Client computer must be able to execute the program
 Java translates program into bytecode, a machine code for
a virtual machine
 Bytecode is transmitted to clients
 Client computer must use either interpreter or JIT
compiler
 Interpreter reads and executes bytecode one by one as
needed
 Just-In-Time compiler translates bytecode to machine code
of the client computer

8. Security Issues
 Java has a security manager that limits the actions
performed by the programs from a server
 No file system access
 No transmission of information across internet to machines
other than client or server

9. Specialization of Interfaces
 Programs at the server is structured in terms of generic
classes, such as window and button
 These classes are the same regardless of the system used
 At run-time these components create peer components for
the client system and is used

10. Java Is Simple
 Simpler than C++
 Many keywords have been eliminated
 No preprocessor
 Much larger library of high-level development tools
 No operator overloading
 No independent functions
 No global variables
 No goto statement
 No structures
 No pointers

11. Java Is Object-Oriented
 The only unit of programming is the class description
 No functions or variables exist outside of class boundaries
 Other languages have object-oriented features on top of the
non-object-oriented language
 Forces all programs into object-oriented structure
 Many benefits of object-oriented design is realized

12. Java Is Network Savvy
 Designed with Internet in mind
 It is possible to construct programs that do not deal with
Internet
 Provides a rich set of tools for programming across a
network
 Classes for describing URLs
 Classes for making connections between client and server
computers
 Classes for execution in controlled environments such as
web browsers

13. Java Is Interpreted
 Java programs are compiled into byte-code that can be
stored on any type machine
 Interpreter is used to read byte-code and execute it
 Generally slower in execution
 A JIT compiler is used to translate byte-code into actual
machine code instructions
 This way makes them run as fast as compiled programs in
the traditional languages

14. Java Is Robust
 Extensive use of exception-handling
 Statements generate exceptions not erroneous operations
 The semantics insist that you must deal with this possibility
 Programmers are forced into thinking about potential
sources of error
 Automatic memory management, or garbage collection
 If programmers forget to release memory resources once
finished with them, applications will eventually fail
 Java run-time system automatically detects and recovers
memory that is no longer being used by the program
 Simplifies the programmer’s task and is more reliable

15. Java Is Secure
 Eliminating pointers removed the most common source of
programming errors
 Array index values are checked for validity
 Java is the first layer in a multilevel security system
 Byte-codes are examined before executed for errors
 Programs are severely restricted in the type operations they
can perform
 Computers are safe when running java programs brought
over the network

16. Java Is Architecture Neutral
 Java byte-code does not correspond to an machine
 A java program is the same on all machines
 Although C++ is a standard language, the libraries needed
to perform activities differ considerably from platform to
another
 Java hides application-specific details under a layer of
abstraction in the standard java library

17. Java Is Portable
 Because the library hides architecture-specific concepts
 Because byte-codes are the same regardless of the machine
 Java programs possess unparalleled degree of portability
 The exact program can be compiled on one system, then
executed on many different types of systems

18. Java Is High-Performance
 Initially heavy performance penalty
 The technology of java execution has rapidly evolved
 JIT compilers allow platform-independent java programs
to be executed with the nearly same run-time performance
as conventional compiled languages

19. Java Is Multithreaded
 One of the first languages designed for the possibility of
multiple threads of execution running in one program
 It is easy to set up multitasking
 The coordination of these parallel processes is relatively
easy

20. Java Is Dynamic
 Moving java programs across the Internet and executing
them on local computers, permits dynamic behavior