Introduction to Java

What is java?

Java is a programming language and a computing platform for application development.
It was first released by Sun Microsystem in 1995 and later acquired by Oracle Corporation in 2010.
In 2006 Sun started to make Java available under the GNU General Public License (GPL).
Lets see the phases of execution of a Java program:

1. Writing of the program is of course done by java programmer
2. Compilation of program is done by javac compiler, javac is the primary java compiler included in java development kit (JDK). It takes java program as input and generates java bytecode as output.
3. In third phase, JVM executes the bytecode generated by compiler. This is called program run phase.

So, now that we understood that the primary function of JVM is to execute the bytecode produced by compiler. Each operating system has different JVM, however the output they produce after execution of bytecode is same across all operating systems. That is why we call java as platform independent language.

Note: To execute any java program, need to install the JDK

Why java language and its features?

Java is popular because of the following features:

1. Simple programming language
2. Object Oriented Language
3. Distributed
4. Robust
5. Architecture Neutral or Machine Independent
6. Portable
7. Interpreted
8. High Performance
9. Multithreaded
10. Dynamic