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Introduction to java


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Introduction to java

  1. 1. Lesson1: JAVAComputer Fundamentals I INTRODUCTION TO JAVA PROGRAMMING
  3. 3. What is Programming Language• High Level Language & Low Level LanguageC++, C, FORTRAN, PASCALAssembly Language or Machine Language• High Level Language Better or Low Level Language. INTRODUCTION TO JAVA PROGRAMMING
  4. 4. Programming languages: A Review• FORTRAN • Ada• COBOL • SQL• BASIC • Lisp• Z80 assembler • Prolog• IBM 360 assembler • Eiffel• PL1 • HTML• SL1 • JavaScript• C • Java• Pascal • Jess• SNOBOL INTRODUCTION TO JAVA PROGRAMMING
  5. 5. Discussion Points• Different levels: high - low• Different implementations: interpreted, compiled• Different paradigms: procedural, declarative, object oriented• Different target domains: data processing, scientific, database manipulation, string manipulation, logic, general purpose …• Different ages: modern/ old fashioned; longevity• Different language features/ constructs INTRODUCTION TO JAVA PROGRAMMING
  6. 6. Common Grounds• Handle data: variables• Handle flow of control:– sequence, selection, iteration• Shared code: sub routines• Data structures: arrays• File handling INTRODUCTION TO JAVA PROGRAMMING
  7. 7. Interpreting and CompilingNOTE : JAVA do both, Interpreting and Compiling INTRODUCTION TO JAVA PROGRAMMING
  8. 8. How JAVA WorksPortability can be Achieved this Way INTRODUCTION TO JAVA PROGRAMMING
  9. 9. Why JAVA• Simple and clean• Object oriented• Portable/ platform independent• Robust• Secure• Multi-threaded• Dynamic• ++ INTRODUCTION TO JAVA PROGRAMMING
  10. 10. Program• A program is a sequence of instructions that specifies how to perform a computation.BASIC Operations in Program:• Input• Output• Mathematical Operations• Testing• Repetition “Programming can also be described as the process of breaking a large, complex task up into smaller and smaller subtasks until eventually the subtasks are simple enough to be performed with one of these basic operations.” INTRODUCTION TO JAVA PROGRAMMING
  11. 11. Debugging• Bugs and Errors• Types of Errors Compile Time Errors Run Time Errors Logic and Semantic Error• Experimental Debugging INTRODUCTION TO JAVA PROGRAMMING
  12. 12. A First Program• Print “Hello World” to the console/**** Created on 19 Sep 2010, 17:56*/ class HelloWorld { public static void main (String args[]) { System.out.println("Hello World!"); } } INTRODUCTION TO JAVA PROGRAMMING
  13. 13. First Steps...• A Java application is made up of a collection of classes• Normally, one (& only one) of these classes should have a method called main• Console output can be achieved using: System.out.print(“a string”); or Err or println or a variable INTRODUCTION TO JAVA PROGRAMMING
  14. 14. Compiling First Program• The file name of this program is:• To compile the program, type: javac• To run the program, type: java HelloWorld• Output should be: Hello World! INTRODUCTION TO JAVA PROGRAMMING
  15. 15. The JAVA Virtual Machine• Java is compiled into an intermediate form (bytecode)• These are the .class files produced by javac• The bytecode is interpreted at runtime by the Java Virtual Machine• Java compiled on one machine (type) can be executed on another (type) INTRODUCTION TO JAVA PROGRAMMING
  16. 16. Standard Java Tools (Java 2 SDK)• javac - the compiler• java - the launcher for Java apps• javadoc - API documentation generator• appletviewer - run & debug applets without a browser• jar - manage Java Archive (JAR) files• jdb - Java debugger• javap - class file dis assembler• ++ INTRODUCTION TO JAVA PROGRAMMING
  17. 17. JDK Kits and Editors• J2SE Available on Sun Website• Editors: Stick with javac, java & your chosen editor (PFE, notepad, JCreator, …)• Java Keywords: 48 reserved Keyword in Java Language.List can be checked at dition/html/lexical.doc.html INTRODUCTION TO JAVA PROGRAMMING