Brief Introduction to Java Technology


  • 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

The Java Platform



The Java Platform


Where Does Java Fit in?

Java Stack

Where Does Java Fit in

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