Transcript Chapter 1 Intro to Java

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1
Introduction to
Java
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History of Java
• Java
– Originally for intelligent consumer-electronic
devices
– Then used for creating Web pages with dynamic
content
– Now also used to:
• Develop large-scale enterprise applications
• Enhance WWW server functionality
• Provide applications for consumer devices (cell
phones, etc.)
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Java Class Libraries
• Classes
– Include methods that perform tasks
• Return information after task completion
– Used to build Java programs
• Java provides class libraries
– Known as Java APIs (Application Programming
Interfaces)
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FORTRAN, COBOL, Pascal and Ada
• FORTRAN
– FORmula TRANslator
• COBOL
– COmmon Business Oriented Language
• Pascal
– Structured programming
• Ada
– Multitasking
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BASIC, Visual Basic, Visual C++, C# and
.NET
• BASIC
– Beginner’s All-Purpose Symbolic Instruction Code
• .NET
– .NET platform
• Visual Basic .NET
– Based on BASIC
• Visual C++
– Based on C++
• C#
– Based on C++ and Java
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Typical Java Development Environment
• Java programs normally undergo five phases
– Edit
• Programmer writes program (and stores program on disk)
– Compile
• Compiler creates bytecodes from program
– Load
• Class loader stores bytecodes in memory
– Verify
• Bytecode Verifier confirms bytecodes do not violate security
restrictions
– Execute
• JVM translates bytecodes into machine language
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Fig. 1.1 Typical Java
development
environment.
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Creating a Program with JCreator
• Click on the JCreator Icon
• IDE
window
appears
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Creating a Program with JCreator
• Click on File, New, then Project
• Project Wizard appears
– Choose Java Application template
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Creating a Program with JCreator
• Give the project a name
• Then click Next
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Creating a Program with JCreator
• You will want the JDK version 1.5
At this point you can click on Finish
• This tab is where you can specify hsa library
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Creating a Program with JCreator
• Now we create our class (the program) with
File, New, and Class
The Class Wizard
appears. Specify a
name for the class
and make sure
Public is chosen
For now, you can proceed
with Finish
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Creating a Program with JCreator
• The wizard creates a template.
• Now complete the program with the
required commands.
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Creating a Program with JCreator
• Run the compiler with Build, and
CompileFile
Build Output shows in bottom pane. This is where
compiler error messages will be displayed.
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Creating a Program with JCreator
• To run the compiled program click on Build,
and ExecuteFile
Without Creating a Project
• Program runs in separate window
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View Flash Presentations
• Creating a workspace, project, and
application
• Writing, compiling, running an application
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Introduction to
Java