HttpSession interface is defined in "javax.servlet.http" package and is used for the purpose of session tracking while working with servlets. Session tracking is a mechanism that is used to maintain state about a series of requests from the same user (that is, requests originating from the same browser) across some period of time.
HttpServletRequest interface is defined in "javax.servlet.http" and is used to retrieve parameters from the request, HTTP request header information, cookies from the request, getting session object to maintain session for the request etc.
HttpServlet class is an abstract class defined in "javax.servlet.http" package and is sub class of GenericServlet class defined in "javax.servlet" package. GenericServlet class is used to define a generic, protocol-independent servlet but HttpServlet class provides an HTTP protocol specific implementation.
Hibernate is popular, powerful, high performance, open source object relational mapping tool for Java platform. Hibernate maps java classes to database tables and provides data query and retrieval facilities also which can reduce much development time in compare to manual data handling in SQL and JDBC.
Java hello world
Java is a high-level object-oriented programming language developed by the Sun Microsystems and is available in different form like JSP, Java Applets, J2EE, JavaBeans, Mobile Java.
Hibernate is an open source software that provides object-relational mapping library for the java language by mapping an object-oriented domain model to a traditional relational database with the help of a framework.
The JVM's heap stores all the objects generating by a running Java program. Java uses the new operator to create objects and memory for new objects is allocated on the heap at run time.
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