Update README.md

Author: Urunov

README.md

@@ -9,7 +9,20 @@ Spring Boot
 * Most Spring Boot applications need minimal Spring configuration. Features. Create stand-alone Spring applications
 
 JPA
-* JPA (The Java Presistence API) = This module deals with enhanced support for JPA based data access layers.Indeed, the JPA is rule of  interface. 
+* JPA (The Java Presistence API) = This module deals with enhanced support for JPA based data access layers.Indeed, the JPA is set of the rules to  interfaces. JPA follows Object-Relation Mapping (ORM). It is a set of interfaces. It also provides a runtime EntityManager API for processing queries and transactions on the objects against the database. It uses a platform-independent object-oriented query language JPQL (Java Persistent Query Language).
 
-    Ex: 
-     Class A, B .... Implemenet Interface
+Why should we use JPA?
+JPA is simpler, cleaner, and less labor-intensive than JDBC, SQL, and hand-written mapping. JPA is suitable for non-performance oriented complex applications.
+
+API (Application programming interface) is a document that contains a description of all the features of a product or software. It represents classes and interfaces that software programs can follow to communicate with each other. An API can be created for applications, libraries, operating systems, etc.
+
+
+JPA Implementations
+JPA is an open-source API. There is various enterprises vendor such as Eclipse, RedHat, Oracle, etc. that provides new products by adding the JPA in them. There are some popular JPA implementations frameworks such as Hibernate, EclipseLink, DataNucleus, etc. It is also known as Object-Relation Mapping (ORM) tool.
+
+JDBC
+* Java Database Connectivity (JDBC) is an application programming interface (API) for the programming language Java, which defines how a client may access a database.
+
+H2
+* H2 is a relational database management system written in Java. It can be embedded in Java applications or run in client-server mode.
+