Which keyword from the following is used to inherit properties from one class into another?
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1. Which of the following is the functionality of ‘Data Abstraction’? Show a) Reduce Complexity b) Binds together code and data c) Parallelism d) None of the mentioned View Answer Answer: a Explanation: An essential element of Object Oriented Programming is ‘Data Abstraction’ which means hiding things. Complexity is managed through abstraction. 2. Which of the following mechanisms is/are provided by Object Oriented Language to implement Object Oriented Model? a) Encapsulation b) Inheritance c) Polymorphism d) All of the mentioned View Answer Answer: d Explanation: None. 3. Which of the these is the functionality of ‘Encapsulation’? a) Binds together code and data b) Using single interface for general class of actions. c) Reduce Complexity d) All of the mentioned View Answer Answer: a Explanation: ‘Encapsulation’ acts as protective wrapper that prevents code and data from being accessed by other code defined outside the wrapper. 4. What is ‘Basis of Encapsulation’? a) object b) class c) method d) all of the mentioned View Answer Answer: d Explanation: Encapsulation is the mechanism that binds together code and data it manipulates, and keeps both safe from outside interface and misuse. Class, which contains data members and methods is used to implement Encapsulation. 5. How will a class protect the code inside it? a) Using Access specifiers b) Abstraction c) Use of Inheritance d) All of the mentioned View Answer Answer: a Explanation: Each method or variable in a class may be marked ‘public’ or ‘private’. They are called Access Specifiers. 6. What is the output of this program? class Test { int a; public int b; private int c; } class AcessTest { public static void main(String args[]) { Test ob = new Test(); ob.a = 10; ob.b = 20; ob.c = 30; System.out.println(" Output :a, b, and c" + ob.a + " " + ob.b + " " + ob.c); } } a) Compilation error b) Run time error c) Output : a, b and c 10 20 30 d) None of the mentioned View Answer Answer: a Explanation: Private members of a class cannot be accessed directly. In the above program, the variable c is a private member of class ‘Test’ and can only be accessed through its methods. 7. Which of the following is a mechanism by which object acquires the properties of another object? a) Encapsulation b) Abstraction c) Inheritance d) Polymorphism View Answer Answer: c Explanation: ‘Inheritance’ is the mechanism provided by Object Oriented Language, which helps an object to acquire the properties of another object usually child object from parent object. 8. Which of the following supports the concept of hierarchical classification? a) Polymorphism b) Encapsulation c) Abstraction d) Inheritance View Answer Answer: d Explanation: Use of Hierarchical classification avoids defining the properities of object explicitly at each level which have acquired their properties from higher levels. 9. Which Keyword from the following is used to inherit properties from one class into another? a) extends b) subclasses c) native d) all of the mentioned View Answer Answer: a Explanation: None. 10. Which of the following concept is often expressed by the phrase, ‘One interface, multiple methods’? a) Abstraction b) Polymorphism c) Inheritance d) Encapsulation View Answer Answer: b Explanation: None. ----------------------------------------------------------------------------------------------------------------------- 1. Which of these is a valid keyword in Java? a) interface b) string c) float d) unsigned View Answer Answer: a Explanation: “String” and “Float” are class types in Java. “unsigned” is a keyword used in C/C++ but not in Java. 2. Which of these is a reserved word in Java Programming Language? a) method b) native c) subclasses d) reference View Answer Answer: b Explanation: “native” is a valid keyword used to modify method declaration. The valid keyword used in Java language for subclassing is “extends” not subclasses. 3. How many reserved keywords are there in Java language? a) 50 b) 52 c) 49 d) 45 View Answer Answer: a Explanation: As of Java 1.5 there are 50 keywords out of which 48 are used(const and goto keywords are unusable keywords). 4. Which of the following is a Literal Representation? a) 100 b) ‘100’ c) Sample d) None of the mentioned View Answer Answer: a Explanation: A constant value in Java is created by using a ‘Literal Representation’ of it. Integer Literals are not enclosed in quotes where as String Literals are enclosed in quotes. 5. What are the types of comments defined by Java? a) Single-line comment b) Multi-line comment c) Documentation comment d) All of the mentioned View Answer Answer: d Explanation: None. 6. Which of the following is readable by both Computer and Human? a) Single-line comment b) Multi-line comment c) Documentation comment d) All of the mentioned View Answer Answer: c Explanation: Documentation comment is used to produce an HTML file that documents the given program. 7. Which of the following ‘Seperator’ is most commonly used in Java program? a) Parenthesis b) Braces c) Comma d) Semicolon View Answer Answer: d Explanation: Semicolon is most commonly used in Java program, which terminates statements. 8. Which of the following is used to name class, method and variables? a) Identifiers b) Keywords c) Both d) None of the mentioned View Answer Answer: a Explanation: Identifiers are used to name classes, methods and variables. 9. ‘Whitespace’ in Java language may be? a) A space b) A new line c) A tab d) All of the mentioned View Answer Answer: d Explanation: None. 10. Which of the following is the output of the program? class Test { public static void main(String args[]) { int num = 10; System.out.println("The value of num is" +NUM); } } a) Compilation error b) Run time error c) Exception d) The value of num is 10 View Answer Answer: a Explanation: Java is case-sensitive. Identifier which is used to name variable and print are different. --------------------------------------------------------------------------------------------------------------------------- Which keyword from the following is used to inherit properties from one class into another A extends B subclasses C Native D All of the mentioned?The keyword “extends” is used while inheriting a class. It defines that the functionality of the superclass is being extended to the subclass.
Which keyword is used to inherited?The keyword used for inheritance is extends.
Which keyboard is used to inherit a class in Java?The extends keyword extends a class (indicates that a class is inherited from another class). In Java, it is possible to inherit attributes and methods from one class to another.
How do you inherit a class?Inheritance allows us to define a class that inherits all the methods and properties from another class. Parent class is the class being inherited from, also called base class. Child class is the class that inherits from another class, also called derived class.
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