Java for students 4 th Edition Pearson-Prentice Hall by Douglas Bell and Mike Parr The background to Java Chapter 1

The History of Java 1950s FORTRAN, COBOL 1960s ALGOL 60, CPL, BCPL 1970s C, UNIX 1980s C s Java (Oak)

Main Features of Java Code similar to C++ Designed for the Internet Portable – can be run on any compiler Java applets are written to be secure –CERT has some advisories about Java Applets) Sun allows for free downloads Browsers are free and Java enabled

What is a program? Instructions (see shampoo bottle) A recipe A musical score

A computer obeys instructions Input/output data Calculations Graphics Response to user input

Programmers select from a list of possible instructions that carry out a specific tasks Music – repeats possible, provides a notation for composer where/when to do so Program sections may need to be repeated and notation provides for that Subtasks – some recipes need tasks to be done before main task may be completed

Java methods (subtasks) may be called by main method or another method when needed

A program may consist of: Sequences Repetition Selection Methods Ready-made objects Objects you write yourself