Question 1 of 25
Hints left: 3
Q1
What is the unique feature of LinkedHashSet?
Q2
What happens if we put a key object in a HashMap which exists?
Q3
How to externally synchronize hashmap?
Q4
Which of these class object can be used to form a dynamic array?
Q5
Which of these method of Array class is used sort an array or its subset?
Q6
Which of these class object uses the key to store value?
Q7
What will be the output of the following Java code? import java.util.*; class stack { public static void main(String args[]) { Stack obj = new Stack(); obj.push(new Integer(3)); obj.push(new Integer(2)); obj.pop(); obj.push(new Integer(5)); System.out.println(obj); } }
Q8
Set has contains(Object o) method.
Q9
What will be the output of the following Java code? import java.util.*; class vector { public static void main(String args[]) { Vector obj = new Vector(4,2); obj.addElement(new Integer(3)); obj.addElement(new Integer(2)); obj.addElement(new Integer(5)); System.out.println(obj.elementAt(1)); } }
Q10
What will be the output of the following Java program? import java.util.*; class Array { public static void main(String args[]) { int array[] = new int [5]; for (int i = 5; i > 0; i--) array[5 - i] = i; Arrays.sort(array); for (int i = 0; i < 5; ++i) System.out.print(array[i]);; } }
Q11
Which of these methods can randomize all elements in a list?
Q12
What will be the output of the following Java program? import java.util.*; class Collection_Algos { public static void main(String args[]) { LinkedList list = new LinkedList(); list.add(new Integer(2)); list.add(new Integer(8)); list.add(new Integer(5)); list.add(new Integer(1)); Iterator i = list.iterator(); Collections.reverse(list); while(i.hasNext()) System.out.print(i.next() + " "); } }
Q13
Which of these is the interface of legacy is implemented by Hashtable and Dictionary classes?
Q14
Which of these methods can be used to obtain a static array from an ArrayList object?
Q15
What will be the output of the following Java program? import java.util.*; class Arraylist { public static void main(String args[]) { ArrayList obj1 = new ArrayList(); ArrayList obj2 = new ArrayList(); obj1.add("A"); obj1.add("B"); obj2.add("A"); obj2.add(1, "B"); System.out.println(obj1.equals(obj2)); } }
Q16
Which of these interface handle sequences?
Q17
If two threads access the same hashmap at the same time, what would happen?
Q18
What will be the output of the following Java code? import java.util.*; class hashtable { public static void main(String args[]) { Hashtable obj = new Hashtable(); obj.put("A", new Integer(3)); obj.put("B", new Integer(2)); obj.put("C", new Integer(8)); System.out.print(obj.toString()); } }
Q19
What will be the output of the following Java program? import java.util.*; class Collection_iterators { public static void main(String args[]) { ListIterator a = list.listIterator(); if(a.previousIndex()! = -1) while(a.hasNext()) System.out.print(a.next() + " "); else System.out.print("EMPTY"); } }
Q20
Which of these package is used for remote method invocation?
Q21
What will be the output of the following Java program? import java.util.*; class Maps { public static void main(String args[]) { HashMap obj = new HashMap(); obj.put("A", new Integer(1)); obj.put("B", new Integer(2)); obj.put("C", new Integer(3)); System.out.println(obj); } }
Q22
What will be the output of the following Java program? import java.lang.reflect.*; class Additional_packages { public static void main(String args[]) { try { Class c = Class.forName("java.awt.Dimension"); Method methods[] = c.getMethods(); for (int i = 0; i < methods.length; i++) System.out.println(methods[i]); } catch (Exception e) { System.out.print("Exception"); } } }
Q23
Which of these class is used for creating a client for a server-client operations?
Q24
Which of these method is used to remove all keys/values pair from the invoking map?
Q25
Which of these method is used to insert value and its key?