Getting Started With Java September 22, 2010
Java Bytecode • Bytecode: is a highly optimized set of instructions designed to be executed by the Java run-time system (JVM) • (The JVM is an interpreter for bytecode)
Compiler Java Bytecode MAC Interpreter Compaq Interpreter HP Interpreter
Platform Independence • A programming language is considered platform independent or portable if the source code created on one computer platform can execute on another without any difficulty.
Compiled and Interpreted • Java uses a compiler to translate the source code by the programmer into bytecode • Java then continues and uses an interpreter to translate the bytecode into executable machine code.
Applications and Applets • A Java program designed to operate inside a webpage is called an applet • A Java program designed to operate in a stand-alone environment is called an application
Our first Data Types • String – stores sequences of characters. • Int – an integer (only whole numbers) • Double- allows for fractional components of numbers (most common) • Float- also allows for fractional components of numbers
Logical Operators • & -- AND • |-- OR • ^ --XOR (exclusive or) • || -- short-circuit OR • && -- short-circuit AND • ! -- NOT