Java in Object Oriented-Programming, Structure Query Language and JavaScript is everything in web, application, and operation. If web, it should be is that opening that you can write the code whatever you develop it with the understanding key concept then last thing is for closing it called SQL: SELECT * nametables FROM product WHERE company App, it should be writing the main.java Then the polymorphism elaborates many forms and inheritance creates a Parent class and Child class and develop that abstract gives a public or private static void before the reality of this explanation then the better & key concepts before encapsulates a way hiding of internal the codes from it.