Introduction to Java Programming Language
- 1. Introduction to Java Programming Language By Norazah Yusof Software Engineering Department Faculty of Computer Science and I f F lt f C t S i d Information Systems ti S t 1
- 2. Outline The origin of Java. The Java history. The Java history. The capabilities of Java programming language. The Java language specifications The Java language specifications The Java API The Java development tools The Java development tools How does byte code makes Java a portable language? 2
- 3. Origin of Java In 1991, Java was developed by a team led by James I 1991 J d l db t l db J Gosling and Patrick Naughton at Sun Microsystems. Originally named Oak ‐ Gosling liked the look of Originally named Oak Gosling liked the look of an oak tree that was outside his window at Sun. 3
- 4. History of Java The challenge: For use in embedded consumer Th h ll F i b dd d electronic appliances ‐ the cable TV switchboxes. Different manufacturers may choose different central Different manufacturers may choose different central processing units (CPUs). The cable TV switchboxes devices do not have a lot of power or memory. The language; Had to be small and generate very tight code. Not be tied to any single architecture. 4
- 5. History of Java A two‐step Java translation process have been developed: Programs written in Java were translated into an intermediate language, known the byte code. Then, the byte code would be translated into machine Th th b t d ld b t l t di t hi language. 5
- 6. History of Java In 1994, Java was used to develop a Web browser, I 1994 J dt d l W bb named HotJava. The browser able to download and run small Java The browser able to download and run small Java programs over the internet, known as the applets. Capable to display animation and interact with the user. In 1995, Netscape incorporated Java technology into its Netscape browser. Then, other Internet companies followed . . . 6
- 7. Java Capabilities Java is a full‐featured and general‐purpose J i f ll f t d d l programming language that is capable of developing a robust mission critical applications for: developing a robust mission‐critical applications for: Desktops Servers Mobile devices The Java programming language is a relatively high‐ level language, class‐based and object‐oriented. 7
- 8. Java Capabilities Java running on the desktop is called application. Java running on the Internet is called applets. Java running on the Internet is called applets Java developed on the server‐side is called servlet. 8
- 9. Java Language Specification Defines the Java standard and the technical definition of the language. definition of the language includes the syntax and semantics of the language. url: java.sun.com/docs/books/jls 9
- 10. Application Program Interface Java application program interface (API) contains the predefined classes and interfaces for developing Java programs. In 1995, Java 1.0 was introduced. With 211 classes and interfaces. In December 1998, Java 2 platform was announced. Applies to current Java technology. l h l 10
- 11. Java API 11
- 12. Java API There are 3 editions of the Java API: Java 2 standard edition (J2SE) Java 2 standard edition (J2SE) • Client‐side standalone applications or applets. Java 2 Enterprise Edition (J2EE) p ( ) • Server‐side applications, such as Java servlets and JavaServer Pages. Java 2 Micro Edition (J2ME) Java 2 Micro Edition (J2ME) • Mobile devices, such as cell phones or pda. 12
- 13. Demonstrate how to link to Java API 13
- 14. J2SE versions and JDK There are many versions of J2SE. Sun releases each version of J2SE with a Java Development toolkit (JDK). Development toolkit (JDK) JDK consists of a set of separate programs for developing and testing Java programs. developing and testing Java programs Each of which is invoked from a command line. For J2SE 5.0, the Java development toolkit is called For J2SE 5 0 the Java development toolkit is called JDK 5 – formerly was known as JDK1.5. The latest version is J2SE 6. 14
- 15. Java Development Tools A software that provides an integrated development A software that provides an integrated development environment (IDE) for rapidly developing Java programs. Java development tools on the market: p NetBeans by Sun (open source) JBuilder by Borland Eclipse by IBM (open source) Other useful tools: Code warrior by Metroworks TextPad Editor JCreator LE Jedit BlueJ 15
- 16. Byte‐Code and the Java Virtual Machine (JVM) i l hi ( ) The Java compiler translates Java programs into byte‐code. Once compiled to byte‐code, a Java program can be used on any computer, making it very portable machine. The Java Virtual Machine (JVM) translates the byte The Java Virtual Machine (JVM) translates the byte code into machine language. 16
- 17. Portability Portable means that a program may be written on one type of computer and then run on a wide variety of computers, with little or no y p modification. Java byte code runs on the JVM and not on any particular CPU therefore, compiled J ti l CPU; th f il d Java programs are highly portable. JVMs exist on many platforms: Windows Macintosh Linux 17
- 18. Portability Byte code (.class) Java Virtual Java Virtual Machine for Windows Machine for Unix Java Virtual Java Virtual Machine for Linux M hi f Li Machine f M i t h M hi for Macintosh 18