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Core Java - Interview Questions and Answers for 'Casting' - 7 question(s) found - Order By Newest

  Q1. What is casting?Core Java
Anonymous
Ans. There are two types of casting, casting between primitive numeric types and casting between object references. Casting between numeric types is used to convert larger values, such as double values, to smaller values, such as byte values. Casting between object references is used to refer to an object by a compatible class, interface, or array type reference

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 Q2. What is Generalization and Specialization in terms of casting ?Core Java
Admin
info@buggybread.com
Ans. Generalization or UpCasting is a phenomenon where a sub class is prompted to a super class, and hence becomes more general. Generalization needs widening or up-casting. Specialization or DownCasting is a phenomenon where a super class is narrowed down to a sub class. Specialization needs narrowing or down-casting.

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   Like         Discuss         Correct / Improve     java   data types   casting  type casting   up casting  type casting   downcasting  type casting   generalization   specialization     Asked in 2 Companies


 Q3. When do you get ClassCastException?

or

What is ClassCastException ?
Anonymous
Ans. As we only downcast class in the hierarchy, The ClassCastException is thrown to indicate that code has attempted to cast an object to a subclass of which it is not an instance.

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 Q4. Difference between implicit and explicit type casting ?
Anonymous
Ans. An explicit conversion is where you use some syntax to tell the program to do a conversion whereas in case of implicit type casting you need not provide the data type.

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 Q5. What is the use of upcasting in Java ?Core Java2017-06-23 12:54:52

Ans. Interfacing

Car extends Vehicle

Car car = new Car();

// now you need to call an API changeTires() which can change tires for all Vehicle Types and accepts argument of type Vehicle and hence you will have to upcast it

changeTires((Vehicle)car);


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   Like         Discuss         Correct / Improve     upcasting  type casting


 Q6. What is TypeCasting ?Core Java2018-07-30 08:40:18

Ans. Assigning a value of one type to a variable of another type is known as Type Casting.

Example :

int x = 10;
byte y = (byte)x;

In Java, type casting is classified into two types, Widening Casting(Implicit) widening-type-conversion and Narrowing Casting (Explicitly done) narrowing-type-conversion.

Widening or Automatic type converion - Automatic Type casting take place when,the two types are compatible and the target type is larger than the source type

Example :

public class Test {
public static void main(String[] args) {
int i = 100;
long l = i; //no explicit type casting required
float f = l;//no explicit type casting required
System.out.println("Int value " i);
System.out.println("Long value " l);
System.out.println("Float value " f);
}
}

Narrowing or Explicit type conversion - When you are assigning a larger type value to a variable of smaller type, then you need to perform explicit type casting.

Example :

public class Test{
public static void main(String[] args) {
double d = 100.04;
long l = (long)d; //explicit type casting required
int i = (int)l;//explicit type casting required
System.out.println("Double value " d);
System.out.println("Long value " l);
System.out.println("Int value " i);
}
}

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   Like         Discuss         Correct / Improve     typecasting  type casting     Asked in 23 Companies


 Q7. Which of the following can throw ClassCastException ?Core Java
a. UpCasting
b. DownCasting
c. Casting to incompatible data type
d. Casting to Strings

Ans.b. DownCasting



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