What is the difference between Xpath and DOM (Document Object Model)?

This is the question asked in most of the interviews of Selenium:

DOM: 

The Document Object Model (DOM) is a cross-platform and language-independent convention for representing and interacting with objects in HTML, XHTML and XML documents. Objects in the DOM tree may be addressed and manipulated by using methods on the objects.

Ex: var element=document.getElementById("intro");

XPATH: 

XPath, the XML Path Language, is a query language for selecting nodes from an XML document. In addition, XPath may be used to compute values (e.g., strings, numbers, or Boolean values) from the content of an XML document.

Ex: //input[@id=”xxx”]

Launched a tutorial on JMeter

This is just an introduction to JMeter. Below are some points covered in this video:

- How to install and configure JMeter?
- Why JMeter and Features of JMeter
- History of JMeter
- Parameters of JMeter
- Introduction to Sampler, Threads, Listeners, Controllers, Timer, Pre-Processor, Post-Processor, Test Plan, Work Bench etc