Collections
- Map implements collection interface?
-
View Hint View Answer Discuss in Forum
NA
Correct Option: C
Collection interface provides add, remove, search or iterate while map has clear, get, put, remove, etc.
- What is the output of this program?
import java.util.*;
public class Output
{
public static void main(String args[])
{
ArrayList object = new ArrayList();
object.add("Y");
object.add("O");
object.add("U");
object.ensureCapacity(3);
object.trimToSize();
System.out.println(object.size());
}
}
-
View Hint View Answer Discuss in Forum
NA
Correct Option: D
trimTosize() is used to reduce the size of the array that underlines an ArrayList object.
- What is the output of this program?
import java.util.*;
public class Result
{
public static void main(String args[])
{
ArrayList object = new ArrayList();
object.add("Y");
object.add("O");
object.add("U");
object.ensureCapacity(5);
System.out.println(object.size());
}
}
-
View Hint View Answer Discuss in Forum
NA
Correct Option: A
Although object.ensureCapacity(5); has manually increased the capacity of object to 5 but the value is stored only at index 3, therefore object.size() returns the total number of elements stored in the object i:e 3, it has nothing to do with ensureCapacity().
- What is the output of this program?
import java.util.*;
public class Result
{
public static void main(String args[])
{
ArrayList object = new ArrayList();
object.add("Y");
object.add("O");
object.add("U");
System.out.println(object.size());
}
}
-
View Hint View Answer Discuss in Forum
NA
Correct Option: D
3
- What is the output of this program?
import java.util.*;
public class Arraylist_Example
{
public static void main(String args[])
{
ArrayList object = new ArrayList();
object.add("L");
object.add("V");
object.add("E");
object.add(1, "O");
System.out.println(object);
}
}
-
View Hint View Answer Discuss in Forum
NA
Correct Option: C
object is an object of class ArrayList hence it is an dynamic array which can increase and decrease its size. object.add(“n”) adds to the array element n and object.add(1,”n”) adds element n at index position 1 in the list, Hence object.add(1,”O”) stores O at index position 1 of obj and shifts the previous value stored at that position by 1.
