I have implemented my domain layer classes and i have used them in a java application. Now i want to use same classes in a java web application,but i dont know how can i do it? In the java aplication we make and run some objects in main(class and method) and use them while program is running. for example an object that hold a collection of data that will be needed for all user requests. My question is: How can i create and hold such objects and data that should be available for all users and clients.