Authentication is one of the most important module or component or plugin for any kind of application either it is web or desktop. We always got first keyword i.e. Authentication in our mind when we thought about development of any new application. In framework, we require a login process for gated content and managing aplication's configurations.
Sometimes we got some different requirements from client side to implement with existing core and contributed modules. As per coding best practice, we always avoid to touch core & contributed modules & themes directly. So, fulfilling client's requirement, we use some methods which is called as hooks in drupal.
As we know that JAVA is a secure platform for any kind of software or web application development but without JSP web application development is quite tough in java. JSP i.e. JavaServer Pages is a server side technology which is having access to JDBC APIs to access or interact with database.
Custom modules or plugins always meet our requirements in any CMS or Framework. Drupal is already having thousands of core and contributed modules on community but sometimes we get some specific requirement for your project which is not available on community.
As we know that today ecommerce plateform is growing too much day by day and everyone wants to be a ecommerce expert. Just by thinking ecommerce, we got first word in our mind is payment integration which is most important phase ecommerce website development.