jdk is an java development kit that contains JREcdevelopment tools
jre is an java runtime environment which is implementation Of JVM that exists physically.Java virtual machine (jvm) ia an abstract machine that bytecode of java can be executed which providing an runtime environments.

In java, it consist various beans such as

Session beans

Entity beans

and message driven

It builds the dynamic websites  with interactive web applications that experts are providing new ideas to write the code  with asp.net

It is one of the main concepts of advanced java which can implemented various designing by using the java projects and ejb projects.