Downloading, Installing and using Java

minutetwitterSoftware and s/w Development

Jun 7, 2012 (5 years and 2 months ago)

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Java

How to find, install and begin
to use the Java programming
language.


A word or two 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



A short look at some old school

languages, BASIC, C and C++


It all begins in the sixties…



BASIC


BASIC stands for Beginner’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
.




C and C++


Developed in 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.



So, what have we learned?

1.
BASIC was an interpreted programming language


2.
“C” was a compiled programming language


3.
“C++” brought object orientation to “C”




Say goodbye to the
seventies and

welcome to a
short
(but hopefully informative)

history of the Java
programming
language


Authentic Seventies

Nerds





James Gosling began developing 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


Java Buzzwords


Simple


Object Oriented


Architecture Neutral


Portable


Multithreaded


High Performance


JIT




Buzzwords glommed from the Core Java 2 book verbatim


FREE



Is Java Interpreted or Compiled?



Is Java Interpreted or 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!




Is Java Object Oriented?




Is Java Object Oriented?

YES!

Every bit of code in a Java program is in a “Class”

Code Reuse, Encapsulation, Polymorphism, Inheritance






DUKE!

Why? Who knows…



Downloading a Java JDK

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



Installing a Java JDK

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)



Now, Lets test it

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”




If we were
lucky we
got
something
that looks
like this…



Help on the Web

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




Remember….

Java is both compiled 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.)




THANK YOU

http:
\
\
remus.rutgers.edu
\
java
\
workshops
\


Any questions or comments can be sent to me

At
biglars@cs.rutgers.edu



Be Good Now…

©2007 Rutgers University & Lars Sorensen