1. Introduction to Java Kiyeol Ryu Java Programming Language

2. The Overview of Java Java Programming Language2 Table of Contents Brief History What is Java Java Applets and Applications Java Programming Environment

3. The Overview of Java Java Programming Language3 Brief History 1991 Green Project (Sun Micro Systems) –Comsumer Electronics 1991 Oak language (Java) 1992 *7 - First Product 1993 CableTV Box - fail 1994 WWW 에 적용 1994 HotJava Browser 1995 Sun World 95 1996 JDK 1.0.2 1997 JDK 1.1 1998 JDK 1.2 –(J2SE SDK 1.2) 2000 J2SE SDK 1.3 2002 J2SE SDK 1.4 1989 WWW (CERN) concept 1993 Mosaic (NCSA) 1993 Netscape M. Adressen, J. Clark 1995 Netscape Licensed Java 1996 MicroSoft Licensed Java 1998 Motorola Licensed Java

4. The Overview of Java Java Programming Language4 What is Java simple object-oriented distributed interpreted robust secure architecture neutral portable high-performance multithreaded dynamic Ref: J. Gosling, et. al., The Java Language, A White Paper, Sun Microsystems, 1994

5. The Overview of Java Java Programming Language5 Java is Simple The syntax of Java is a cleaned-up version of the syntax for C++. –header files –pointer –unions –operator overloading –virtual base classes –typedef –stuct –explicit memory management –etc. C++ C Java

6. The Overview of Java Java Programming Language6 Java is Object-Oriented Models real world entities as objects Abstracts out data as classes Reuses classes through inheritance

7. The Overview of Java Java Programming Language7 Java is Distributed Extensive TCP/IP networking capabilities Interactivities with protocols to retrieve information such as HTTP, FTP Ease of accessing remote files

8. The Overview of Java Java Programming Language8 Java is Interpreted The java interpreter can directly execute instructions in its object code. Java bytecode Architecture-neutral

9. The Overview of Java Java Programming Language9 Java is Robust No pointer Array bounds checking Exception handling Byte code verification

10. The Overview of Java Java Programming Language10 Java is Secure With robustness Bytecode verifier Class loader Sandbox model Digital signature

11. The Overview of Java Java Programming Language11 Java is Architecture Neutral Java Source Java Compiler Java Byte Code network Bytecode Verifier Class Loader JIT compiler InterpreterRuntime hardware Compile time Runtime

12. The Overview of Java Java Programming Language12 Java is Portable Architecture independent Ints are always Ints and are always 32-bits 2’s complemented integers. User interfaces via an abstract window system so the windows can be implemented on UNIX, PC and Mac

13. The Overview of Java Java Programming Language13 Java is Multithreaded Many simultaneous activities in “one” program Better interactive performance Better real-time behavior

14. The Overview of Java Java Programming Language14 Java is Dynamic. Code can be added to a running program –useful in evolving environment Reflection capability –to analyze objects in runtime

15. The Overview of Java Java Programming Language15 Applying Java Java Application –Stand-alone program –Java interpreter executes applications Java Applet –Java code embedded in HTML documents –Java-enabled browser executes(interprets) applets Java Servlet –Web component that generates dynamic content –Run by a web server Java Server Page(JSP) –To develop dynamic web pages –a JSP page is an HTML page that contains java code –Run by a web server

16. The Overview of Java Java Programming Language16 Java Application Sample application class HelloWorldApp { public static void main (String args[]) { System.out.println (“Hello World!”); }

17. The Overview of Java Java Programming Language17 Compile and Execute Java compiler generates Java bytecode Java interpreter executes Java bytecode Java Program Java Classes (Bytecodes) Java Compiler Java Interpreter Results

18. The Overview of Java Java Programming Language18 Java Applet Sample HTML <applet code=HelloWorld.class width=100 height=100 > Web Browser Applet (Java classes) HTML Web Server 1.load HTML 2.load applet 3.run applet 1 2

19. The Overview of Java Java Programming Language19 Java Programming Environment Java 2 Standard Edition(J2SE) SDK

20. The Overview of Java Java Programming Language20 Advanced Java Technology Java Beans Java IDL Jini technology Java Message System(JMS) Enterprise Java Beans(EJB) Java Server Pages(JSP)...