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Java Programming, 3e
Concepts and Techniques
Chapter 1
An Introduction to
Java and
Program Design
Chapter Objectives
• Describe characteristics of Java
• Explain the uses of Java and identify types
of Java programs
• Identify the phases in the program
development life cycle
• Define programs, programming, and
applications
• Read, explain, and create a class diagram
Chapter 1: An Introduction to Java and Program Design
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Chapter Objectives
• Read, explain, and create an event
diagram
• Explain object-oriented programming
(OOP) and object-oriented design (OOD)
• Define the terms objects, attributes,
methods, and events
• Define and explain encapsulation,
inheritance, and polymorphism
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Chapter Objectives
• Describe rapid application development
(RAD)
• Identify key components of the Java
Software Development Kit (SDK)
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Introduction
• A program is a step-by-step series of instructions
for a computer
• Computer programming is the process of writing
these instructions
• Programmers, or developers, design and write
programs using a programming language or
development tool
• Java is a programming language that provides
the structure for efficient and economical
programs
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What Is Java?
• High-level language
• Object-oriented
– Data and operations are packaged into a
single unit called an object
• Basic syntax derived from C, C++, and
Smalltalk
– Designed by a team from Sun Microsystems
led by James Gosling in the early 1990’s
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What Is Java?
• Parsimonious
– Compatible with older versions
• Robust
– Strongly typed and incorruptible data
• Secure
– Protection against misuse of code
• Portable
– Platform-independent
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Java Program Types
•
•
•
•
•
Console and Windowed applications
Applets
Servlets
Web Services
JavaBeans
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Console Applications
• Stand-alone programs using a commandline interface
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Windowed Applications
• Stand-alone programs using a graphical
user interface (GUI)
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Applets
• Client-side programs executed as part of a
displayed Web page
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Servlets
• Server-side programs hosted and run on a
Web server
• Used in conjunction with Java Server
Pages (JSP) to provide sophisticated
server-side logic
• Enable connections to server databases
through Java Database Connectivity
(JDBC)
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Servlets
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Web Services
• Services receive information requests over
the Web and return the requested data
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JavaBeans
• Reusable software components
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Programming a Computer
• Companies need developers to build
general application software packages
• Custom applications are built for specific
needs
• Existing programs need maintenance,
monitoring, and upgrades
• New applications will be needed due to
emerging technologies
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Chapter 1: An Introduction to Java and Program Design
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Program Development Cycle
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Phase 1 – Analyze the
Requirements
• Verify that the requirements are clear and
complete
• Evaluate the problem to determine that it
is solvable using a program
• List the required input and output data
• Determine whether the input data is
available for testing
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Phase 1 – Analyze the
Requirements
• Ensure that a solution, or algorithm, can
be developed with the information
provided in the requirements
• Verify the user interface specifications
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Phase 2 – Design the Solution
• Develop a logical model that illustrates the
sequence of steps you will take to solve
the problem
• Use design tools such as storyboards,
class diagrams, flowcharts, and
pseudocode to outline the logic of the
program
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Phase 2 – Design the Solution
• Storyboards are sketches of the user
interface
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Phase 2 – Design the Solution
• Class Diagrams illustrate the attributes
and methods of a class of objects
– Attributes define the characteristics of a class
– Methods are instructions a class uses to
manipulate values, generate outputs, or
perform actions
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Phase 2 – Design the Solution
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Phase 2 – Design the Solution
• Flowcharts graphically represent the logic
used to develop an algorithm
• Control structures allow the programmer to
specify the code that will execute only if a
condition is met
• Flowcharts use pseudocode, English, or
mathematical notation inside symbols to
represent the steps of a solution
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Phase 2 – Design the Solution
• Pseudocode is an English representation
of how the program code should be written
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Phase 3 – Validate the Design
• The programmer steps through the
solution with test data
• The user agrees that the program design
solves the problem put forth in the
requirements
• The user verifies that the initial
requirements document contains all
necessary requirements
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Phase 4 – Implement the Design
• Write the code that translates the design
into a program
• Create the user interface
• Create comments within the code that
explains the purpose of the code
• Unit testing
– Test the code as it is written
• Test related code
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Phase 4 – Implement the Design
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Phase 5 – Test the Solution
• Create a test plan with test cases of
sample input data and expected output
• Perform integration testing to ensure that
components interact correctly
• Test boundary values
• Document any problems
– If results are unsatisfactory, a new iteration of
the development cycle begins
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Phase 6 – Document the Solution
• Requirements documents, program design
documents, user interface documents, and
documentation of the code
• Test cases and proof of successful
completion of testing
• Program code should be archived
electronically
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Object-Oriented Programming and
Design
• Object-oriented programming
– Data and the code that operates on the data
are packaged into a single unit called an
object
• Object-oriented design
– Identifies how objects interact with each other
to solve a problem
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Object-Speak
• Aggregation
– The concept of an object composed of
another object
• Generalization hierarchy
– A tool displaying a hierarchy of classes,
including superclasses and subclasses
• Instance
– A specific use of a class
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Object-Speak
• Operation
– Activity that reads or manipulates the data of an
object
• Message
– Activates the code to perform one of the operations
• Trigger
– Causes the message to be sent
• Event
– The process of a trigger sending a message that
results in an operation
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Object-Speak
• An event diagram graphically represents
relationships among event and operations
• Useful for designing event-driven programs
• Part of the Unified Modeling Language (UML)
– The UML provides a standardized model to describe
object-oriented designs graphically
– The UML is a system of symbols to represent object
behavior and program behavior
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Encapsulation
• The process of hiding the implementation
details of an object from its user
• The user is shielded from the system’s
complexity
• Information hiding provides access to an
object only through its messages
• Objects can be modified without requiring
application modification
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Inheritance
• An efficient way to reuse code by defining
a subclass as an extension of another
class
• The subclass inherits all the data and
functions of the superclass
• The subclass has at least one attribute or
method that differs from its superclass
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Polymorphism
• Allows an instruction to be given to an
object using a generalized command
• The same command will obtain different
results depending on the object receiving
the command
• The specific actions internal to the object
are encapsulated from the user
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Rapid Application Development
• Pre-built objects speed up program development
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What Is the Java SDK?
• The Java Software Development Kit (SDK) is a
programming package to develop Java applications
• The Java Runtime Environment (JRE) provides the tools
to deploy Java applications
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Features of the J2SE
• The Java Compiler
– Converts code into bytecode
• The Java Virtual Machine
– Contains an interpreter to execute the bytecode
• The Java API
– The standard set of packages available in Java
• The Java Applet Viewer
– Mini browser to display Java applets
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Other Java Development Tools
• VATE (value-added text editor)
– Color codes elements and numbers lines
– Examples: TextPad, JCreator, JGrasp
• IDE (integrated development environment)
– Builder tool to aid coding and debugging
– Examples: Sun ONE Studio, JBuilder, Visual Age,
Simplicity
• Web server
– Deploys servlets
– Example: Tomcat
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Chapter Summary
• Describe characteristics of Java
• Explain the uses of Java and identify types
of Java programs
• Identify the phases in the program
development life cycle
• Define programs, programming, and
applications
• Read, explain, and create a class diagram
Chapter 1: An Introduction to Java and Program Design
48
Chapter Summary
• Read, explain, and create an event
diagram
• Explain object-oriented programming
(OOP) and object-oriented design (OOD)
• Define the terms objects, attributes,
methods, and events
• Define and explain encapsulation,
inheritance, and polymorphism
Chapter 1: An Introduction to Java and Program Design
49
Chapter Summary
• Describe rapid application development
(RAD)
• Identify key components of the Java
Software Development Kit (SDK)
Chapter 1: An Introduction to Java and Program Design
50
Java Programming, 3e
Concepts and Techniques
Chapter 1 Complete