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Java
This document provides an overview of how to install and begin using the Java programming language. It first gives a brief history of Java and its origins in the 1990s at Sun Microsystems. It then explains how to download and install the Java Development Kit (JDK) on a Windows computer, covering creating a temp directory, downloading the offline JDK file from Oracle's website, installing it typically in the C:\Java directory, and adding the bin path to the system PATH environment variable. Finally, it demonstrates a simple "Hello World" Java program using the javac compiler to create bytecode and java to run the program, showing the basic workflow of Java's compile and interpret process.
Java
- 1. Java How to find,install and begin to use the Java programming language.
- 2. A word ortwo on the history of some old fashion programming languages A small history of Java… How do I install it on my computer? How do I use what I just installed? What we’re going to cover
- 3. A short lookat some old school languages, BASIC, C and C++ It all begins in the sixties…
- 4. BASIC BASIC stands forBeginner’s All-purpose Symbolic Instruction Code. It was designed in 1963 at Dartmouth college. It was designed to make it easy for non-technical people to write computer programs. BASIC programs were like grocery lists. You told the program what you wanted to do and it did it in order. BASIC was Interpreted.
- 5. C and C++ Developedin the early seventies, “C” became the de-facto language for microcomputer programming in the seventies and eighties. “C” was not interpreted, it was compiled. __________ Later, in the early eighties, C++ introduced object orientation to the C world. Originally called “C with Classes”, Bjarne Stroustrup developed the additions to C that, in 1985, became C++. OO is when programmers try to mimic the real world more closely and make programs act like “objects” and not just be grocery lists.
- 6. So, what havewe learned? 1. BASIC was an interpreted programming language 2. “C” was a compiled programming language 3. “C++” brought object orientation to “C”
- 7. Say goodbye tothe seventies and welcome to a short (but hopefully informative) history of the Java programming language Authentic Seventies Nerds
- 9. James Gosling begandeveloping Java beginning in 1991 It was first called “Project Green” and ‘Oak” First developed for remote cable TV boxes James Naughton creates “HotJava” in 1995. it’s a web browser that lets you run “Applets”. The entire browser is written in Java. In 1998 Java 1.2 is released Java just released version 1.6 or J2SE 6… James Gosling Circa 1971 James Gosling Today
- 10. Java Buzzwords Simple Object Oriented ArchitectureNeutral Portable Multithreaded High Performance – JIT Buzzwords glommed from the Core Java 2 book verbatim
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- 12. Is Java Interpretedor Compiled?
- 13. Is Java Interpretedor Compiled? BOTH!! Java programs are compiled to Bytecode Bytecode is then interpreted by a JVM, or Java Virtual machine. The virtual machine is what runs your program It’s the JVM that cares about your Operating system, NOT THE PROGRAM! WORA - Write Once, Run Anywhere!
- 14. Is Java ObjectOriented?
- 15. Is Java ObjectOriented? YES! Every bit of code in a Java program is in a “Class” Code Reuse, Encapsulation, Polymorphism, Inheritance
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- 18. Downloading a JavaJDK You want a JDK, not just a JRE Create a “Temp” directory on your PC or laptop Go to http://java.sun.com Go to the “Popular Downloads” section and select “Java SE” Select a JDK without Netbeans (We’ll talk about this later) Agree to the accept the use policy Right Click and Save the Offline Windows JDK to your temp dir
- 19. Installing a JavaJDK Go to your “Temp” dir using Windows Explorer Make sure no other apps are running and double click the install program you just downloaded. Follow the steps. I install in C:Java Watch fom multiple JREs and JDKs! In Windows the Registry runs the show now, not the JAVA_HOME env variable Test with a Command Prompt Window and “java –version” Add C:Java”Java ver”bin to your PATH var Be sure to add “current directory” to the CLASSPATH (if you had one)
- 20. Now, Lets testit DOS - Command Prompt Make a directory structure Type “Edit” and Voila PSVM Test JAVAC and JAVA Create Bytecode ( the *.class file) with “Javac” Run Program with “Java”
- 21. If we were luckywe got something that looks like this…
- 22. Help on theWeb http://java.sun.com/javase/6/docs/api/ http://www.javaranch.com http://java.sun.com/docs/books/tutorial/ http://www.sorcon.com/java2/ http://remus.rutgers.edu/freestuff Got an Error? Just type it verbatim into Google and you usually can find the answer to your question or solve your problem. Wikipedia is a good place to get background and history On anything, and Java is no exception
- 23. Remember…. Java is bothcompiled and interpreted Java is Object Oriented http://java.sun.com is Java’s home You want the Java Development Kit (JDK) , not a JRE or J2EE Take your time, use temp directories for setup files Test with a simple “Hello World” after you install Use the Web for help (Google errors, javaranch, etc.)
- 24. THANK YOUhttp:remus.rutgers.edujavaworkshops Any questionsor comments can be sent to me At biglars@cs.rutgers.edu Be Good Now… ©2007 Rutgers University & Lars Sorensen