Why selenium ?

  • It can be used for many OS (almost all the OS).
  • Supports many programming language. Ex- Java, Python, C# and Ruby etc.
  • It’s an open source as well as very effective.
  • Test script execution is much faster than QTP.
  • Easy to learn and understand.

What is the difference between Scripting and Programming language ?

  • By using programming language, we can develop application.
  • Scripting language is used for testing/validating application. Using scripting, application can not be developed.

What is a Program ?

  • Program is a set of instruction.

Here, we are going to learn selenium using core-Java.

Interpreter- One line at a time and convert it into LLL.
Compiler- It take entire program in one shot.

JVM- Java virtual Machine- It’s work as an interpreter.
JRE- Java run time environment.

Why Java is so popular or Best feature of Java ?

  •  Java is platform independent. 
    Explanation- Suppose if we have executed byte code, then JRE is sufficient to run that. (as explained in above diagram). 
                 To make platform independent convert the java code into byte code. And as we can execute this byte code on any OS that’s why Java is called as platform independent.


Source: http://selenium-makeiteasy.blogspot.com