Brief Introduction to Java Technology

 Topics

• Historical background
• What is Java technology?
• Types of Java platforms
  • Java SE (Focus of this course)
  • Java EE
  • Java ME
• Where does Java fit in?

Historical Background:

When and Who Created Java?

• Java was created in 1991 by James Gosling of Sun Microsystems.
• It was initially called Oak, named after the tree outside Gosling's window, but its name was changed to Java because the name Oak was already taken by someone else as a trademarked name

Why Java was created?

• The original motivation for Java was to create a platform independent language that could be used for writing applications for the consumer devices like toasters and refrigerators
  • This motivation was never realized, however
• At about the same time, the Web was gaining popularity. Gosling realized that Java could be used for Internet programming
  • The “platform independent language” and “platform independent programs” perfectly fit the need of the internet at the time where programs can be downloaded to different type of browsers – they are called “applet”, which is still a popular way of using Java

What is Java Technology?

The Java technology is all of the following

1. A programming language
2. A development environment
3. A runtime environment (A runtime platform)

1.Java Technology: Programming Language

• As a programming language, Java can create all kinds of applications
  • Desktop applications such as word processing application (via Java SE)
  • Enterprise applications such as inventory management systems (via Java EE)
  • Mobile applications that run on mobile devices such as phones and tablets (via Java ME)
  • Internet applications that can run inside browsers (Applet)
  • Even tiny applications that run on credit-card like devices (via Java Card)
  • Big data analysis application (via Hadoop)

2.Java Technology: A Development Environment

• As a development environment, Java technology provides you with a set of tools
  • A compiler (javac)
  • A runtime platform (java)
  • A documentation generator (javadoc)
  • A set of libraries (*.jar files)
• JDK (Java Development Kit) provides all of the above
  • You download JDK from Oracle website
• There are many Java IDE's that provide integrated development environments (JDK plus more)
  • Eclipse, NetBeans, IntelliJ IDEA, etc

3.Java Technology: A Runtime Environment

• Java applications runs over Java Runtime Environment (JRE)
  • JRE is also called Java Virtual Machine (JVM)
• JRE examples
  • JRE over which a desktop application runs (java.exe)
  • JRE is built inside a browser (so that it can run applet)
  • JRE that comes with server (Tomcat, GlassFish)
  • JRE on mobile device platforms (built in a device) 
• It is these JRE's of all these diverse set of platforms that provides the common runtime environment for Java programs
  • “Write once Run everywhere”

Types of Java Platform:

The Java™ Platform

Where Does Java Fit in?

Java Stack

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