Visual and Internet Programming using JAVA ICT 6007 Visual and Internet Programming using JAVA Mohammad Tanvir Alam Lecturer IICT,BUET Home page: http://teacher.buet.ac.bd/teacher/mtanviralam/

Feel free to e-mail me anytime Administrative Contact mtanviralam@iict.buet.ac.bd mtanvir96@yahoo.com Course Group www.groups.yahoo.com/group/ict6007 Course handout Or http://teacher.buet.ac.bd/teacher/mtanviralam/ Please join the group to get lecture materials and participate in group discussion Feel free to e-mail me anytime

Java How to Program (5th or 6th edition) Deitel & Deitel Reference Book Java How to Program (5th or 6th edition) Deitel & Deitel Programming Tools Java 2 Standard Edition IDE JBuilder 7.0 or later Kawa 4.0 or later

Chapter 1 Outline History of C++ History of Java Java Class Libraries BASIC, Visual Basic, Visual C++, C# and .NET Basics of a Typical Java Environment Thinking about Objects

Machine Languages, Assembly Languages and High-Level Languages “Natural language” of computer component Machine dependent Assembly language English-like abbreviations represent computer operations Translator programs convert to machine language High-level language Allows for writing more “English-like” instructions Contains commonly used mathematical operations

Compiler VS Interpreter Compiler convert to whole program to machine language Interpreter Execute high-level language programs without compilation line by line

History of C++ C++ Objects Evolved from C Provides object-oriented programming capabilities Objects Reusable software components that model real-world items

History of Java Java Originally for intelligent consumer-electronic devices Then used for creating Web pages with dynamic content Now also used for: Develop large-scale enterprise applications Enhance WWW server functionality Provide applications for consumer devices (cell phones, etc.)

Java contains class libraries Java Class Libraries Classes Include methods that perform tasks Used to build Java programs Java contains class libraries Known as Java APIs (Application Programming Interfaces)

BASIC, Visual Basic, Visual C++, C# and .NET Beginner’s All-Purpose Symbolic Instruction Code Visual Basic .NET Framework Class Library (FLC) Visual C++ Microsoft Foundation Classes (MFC) C# C-Sharp .NET .NET platform

Basics of a Typical Java 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 Verifier ensures bytecodes do not violate security requirements Execute Interpreter translates bytecodes into machine language

Fig. 1.1 Typical Java environment. Primary Memory . Disk Editor Compiler Class Loader Program is created in an editor and stored on disk in a file ending with .java. Compiler creates bytecodes and stores them on disk in a file ending with .class. Class loader reads .class files containing bytecodes from disk and puts those bytecodes in memory. Phase 1 Phase 2 Phase 3 Bytecode Verifier Bytecode verifier confirms that all bytecodes are valid and do not violate Java’s security restrictions. Phase 4 Interpreter Interpreter reads bytecodes and translates them into a language that the computer can understand, possibly storing data values as the program executes. Phase 5 Fig. 1.1 Typical Java environment.

Thinking About Objects (cont.) Reusable software components that model real-world items Look all around you People, animals, plants, cars, etc. Attributes Size, shape, color, weight, etc. Behaviors Babies cry, crawl, sleep, etc.

Thinking About Objects (cont.) Object-oriented design (OOD) Models real-world objects Models communication among objects Encapsulates attributes and operations (behaviors) Information hiding Communication through well-defined interfaces Object-oriented language Programming in object oriented languages is called object-oriented programming (OOP) Java