Revature Interview UPDATED Exam Questions and CORRECT Answers

Revature Interview UPDATED Exam Questions and CORRECT Answers Object -oriented programming (OOP) - Correct ANSWER - a programming language model organized around objects that have data and methods that form the object. It's an instance of a class. four main concepts: 1. Encapsulation 2. Abstraction 3. Inheritance 4. Polymorphism. Variables - Correct ANSWER - A structure for temporarily storing data in your computers memory 1. primitive variables - data types like integers, decimals, and alphanumeric characters 2. reference variables - store memory addresses where objects are located. use a class (name) as their type and can only point to objects that are instances of the class that is their type Arrays - Correct ANSWER - A collection of primitive values or object reference organized with an index. A specific amount of memory is reserved for an array based on the size and data type Instance variable - Correct ANSWER - declared in the class scope { } denote a change in scope What is DBMS? - Correct ANSWER - Database Management System What is RDBMS? - Correct ANSWER - Rational Database Management System - stores data into tables with columns and rows Ex. SQL Server class - Correct ANSWER - a blueprint or prototype from which objects are created. a representation of a type of object. Example: class called Vehicle describes the minimum things that a vehicle is. Inheritance - Correct ANSWER - Inheritance allows a class to use the properties and methods of another class. Allows parent/child relationship. Example: car and truck inherit functions of vehicle but car is not truck or vice versa. A class inherits fields and methods from all its superclasses, whether direct or indirect. A subclass can override methods that it inherits, or it can hide fields or methods that it inherits. Interface - Correct ANSWER - a description of the actions that an object can do. an Interface is a description of all functions that an object must have in order to be an "X". http://images.slideplayer.com/14/4328130/slides/slide_3.jpg Why use an interface? - Correct ANSWER - main use is polymorphism, or the ability to perform the same operation on a number of different objects. Package - Correct ANSWER - a namespace that organizes a set of related classes and interfaces. Used to keep things organized by placing related classes and interfaces into packages. Used in Java in order to prevent naming conflicts. How to create and use objects - Correct ANSWER - You can declare, instantiate using new keyword, or initialize by using new and calling constructor You can call object fields using the dot method and calling its functions Encapsulation - Correct ANSWER - the principle of information hiding and wrapping code together into a single unit. data is not accessed directly API - Correct ANSWER - Application Programming Interface - Contains the complete listing for all packages, interfaces, classes, fields, and methods supplied by the Java SE platform Association - Correct ANSWER - a relationship between two classes. there is no owner between objects. For example, a teacher *has -a* or *teaches* a student. There is no ownership between the teacher and the student Aggregation - Correct ANSWER - a weak type of Association with partial ownership. For an Aggregation relationship, we use the term *uses*. For example, a person has an address. if you take away the address, nothing really changes the person. Composition - Correct ANSWER - a strong type of Association with full ownership. This is strong compared to the weak Aggregation. For a Composition relationship, we use the term *owns*. For example, a car has an engine. if you take away that engine the car doesn't function anymore. Abstraction - Correct ANSWER - its a concept that places emphasis on what an object is or does rather than how it works. Polymorphism - Correct ANSWER - The ability of different objects to respond differently to identical messages. Ex: Triangle and Rectangles are Shape objects. Shapes are drawn but each are drawn in different ways. non-static field (instance variable) - Correct ANSWER - Non-static fields are known as instance variables because their values are unique to each instance of a class. Ex: currentSpeed of one bicycle is independent from the currentSpeed of another