Intro and Hello World/Java

CS

Outline

Lecture material:

• History & Today
• Acronyms
• Characteristics
• Compiling
• Running
• Documentation

Material

Start with Java history

• Why Java was invented
• Inspiration came from universal "virtual machine" idea
• Location/companies/people
• Evolution of Java over time

Characteristics/Java Today

• Noun based object oriented programming language - everything is an object
• Programmers today have many more languages to choose from
• Java is a standby but important to know advantages and disadvantages
• Oracle owns the Java language

Aconyms Galore

• J2SE
• J2ME
• J2EE
• JVM
• JRE

Compiling

• Java is a compiled language
• Compiling basic hello world program from command line
• Compiling basic hello world program from IDE
• Most people use IDE
• External libraries with Jar files, won't go into Java project management

Running

• Compiler converts Java code into universal Java bytecode, same on every device
• Java byecode is run by the JVM; JVM is different on each device

Documentation

• Oracle owns Java, meaning they control it, but Java source code has been released
• Oracle maintains control of Java source code, and maintains documentation for Java
• Catch-all place to go for information about Java