Wipro PRP - 15th June

Which does autoboxing or unboxing in Java?

• Compiler

• Runtime

• Third party tools

• JDK

Which system property stores installation directory of JRE?

• user.home

• java.class.path

• java.home

• user.dir

Which Java version introduced the feature Autoboxing and Unboxing?

• Java 4

• Java 5

• Java 6

• Java 7

What is the need for Autoboxing and Unboxing in Java?

• Reduces code to be written by developers to convert from Wrapper to Primitive vice versa

• Compile time is reduced due to fixed methods followed to automatically convert Objects and Primitives

• Auto-unboxing improves memory efficiency by converting Wrapper to Primitive and process when object version is not needed

• All the above

Choose the right statement which does autoboxing in Java?

• Integer temperature1 = 100;

• int temperature2 = 101;

• Integer temperature1 = 100;
  int temperature2 = 101;

• Double temperature1 = 100;
  int temperature2 = 101;

What is the output of the below java code with autoboxing?

public class AutoBoxingTest2
{
  static void show(int reading)
  {
    System.out.println("Reading: " + reading);
  }
  public static void main(String[] args)
  {
    Integer a = Integer.valueOf(10);
    show(a);
  }
}

• Reading: 0

• Reading: 10

• Compiler error

• None

What are the components of a marker interface?

• Fields and methods
  

• No fields, only methods

• Fields, no methods

• No fields, No methods

Which of these exception is thrown in cases when the file specified for writing is not found?

• IOException

• FileException

• FileNotFoundException

• FileInputException

Which of these values is returned by read() method is end of file (EOF) is encountered?

• 0

• 1

• null

• -1

Which of these exception is thrown by close() and read() methods?

• IOException

• FileException

• FileNotFoundException

• FileInputOutputException