State, Timing and Interaction Overview Diagrams for Library Managment System

Class diagram

State Machine Diagrams

State Chart Diagram for Book

 

Drawn using Umlet

State diagram for Membership

Timing diagrams

Drawn using Visual Paradigm

 

Interaction Overview Diagrams

                       

 

                                                                                                                                                                                       

                                                   

Static Keyword in Java

Static variable can be used to refer the common property of all objects.
Static variable gets memory only once in class area at the time of class loading. if any object changes the value of static variable, it will retain its value.
A static method can be invoked without the need for creating an instance of a class. Ex: className.staticMethod
Static method can only access static data member and can change the value of it.
The static method can not use non static data member or call non-static method directly.

Above content taken from http://www.javatpoint.com/static-keyword-in-java

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What is JRE?

Java Run Time Environment (JRE)   is implementation of Java Virtual Machine (JVM) that is used to interpret the byte code generated by compiling the java program