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?
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
- A programming language
- A development environment
- 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?