Basic knowledge of SSL, HTTPS, and Certificates is a must for any Java programmer, especially those who are working in financial and security-sensitive applications, which are accessed over the internet. In this article, I am giving you an overview of these three key concepts and How SSL, HTTPS, and certificates work together, to provide secure communication between client and server. Security is a major concern while developing web applications, which are accessible using the HTTP protocol. Since HTTP protocol transfers data in plain text format, it's not safe for transferring sensitive information like username, password, social security number (SSN), or credit card details for online shopping.