- 2 What Is The Relationship Between A Class And An Object A A Class Is An Abstraction Of An Object B An Object Is An Ab 1 (88.21 KiB) Viewed 27 times
2 what is the relationship between a class and an object A. A class is an abstraction of an object B. An object is an abstraction of a class C. Objects are superclasses of classes D. A class is a concrete instance of an object 9. Which of the following statements is correct ( ) A. Java code can be understood and executed directly by the computer B. JDK is a kind of software that can run Java programs C. Java uses compiler to execute code D. The source program of Java is saved with the "java" extension 10. The wrong statement about class is (). A. Class is a composite data type B. Class contains variables and operations related to variables C. Class is abstracted, so class data cannot be accessed D. Classes can be regarded as abstractions of things with common properties and behaviors: 11. In the following statements about object-oriented programming, the incorrect one is (). A. Object encapsulates data and behavion B. Object is the core of object-oriented technology. In object-oriented programming, object is the concrete part of classi C. A class is a collection of objects with the same characteristics (attributes) and common behaviors (Methods) D. Class modifiers can be abstract, static, or final 12. The correct statement about class members is ( ) A. Instance methods can use class variables B. Instance variables can be used in class methods C. Instance methods can be called directly with class names D. Class methods can only be called with class names, not object names 13. For a three-digit positive integer n, the expression of the number on its hundred digit is (). A. n/100 B. (n-n/100 100/10 C n %10 D. n/100 % 10 14. In the following statements on construction methods, the incorrect one is (). A. Method name of construction method must be consistent with class name B. The construction method does not return a value type, it can be void type. C. If you do not define any construction methods in a class, the compiler 2 automatically adds a construction method without any parameters D. Construction methods can be overloaded 15. In OOP, inheritance refers to ( ) A. Similar properties of a group of objects B. One object has the properties of another C. Common properties among objects D. The mechanism of sharing properties and operations between classes 16. Which of the following declarations of class is correct? ( ) A. abstract final class People...) B. abstract private go()...) C protected private digit D. public abstract class Bike...) 17. In the following statements about interface, the correct one is (). A. Interface is different from the abstract class B. To implement an interface, at least one method of the interface must be implemented C. There can be no inheritance relationship between interfaces D. A class cannot implement multiple interfaces 18. If a class is declared as final, the incorrect statement is (). A. Indicates that this class is final B. Indicates that this class is a root class C. Methods in this class cannot be overridden D. Variables in this class cannot be hidden 19. In the following description of polymorphism, the incorrect one is (). A. Polymorphism refers to "one definition, multiple implementations" B. There are three types of polymorphism: dynamic polymorphism, static polymorphism, and default polymorphism C. Polymorphism is not used to speed up code D. Polymorphism is one of the core characteristics of OOP 20. In Java, two interfaces B and C have been defined. To define a class that. implements these two interfaces the correct statement is) =