Java Programming · all questions

Java Collections Framework
practice.

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179

Questions

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Q101

Set has contains(Object o) method.

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Q102

Which of these package is used for remote method invocation?

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Q103

What is the relation between hashset and hashmap?

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Q104

Which of these return type of hasNext() method of an iterator?

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Q105

Which of these is an incorrect form of using method max() to obtain a maximum element?

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Q106

Which of these methods is used to obtain an iterator to the start of collection?

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Q107

What will be the output of the following Java program?

import java.util.*; 
class Output 
{
    public static void main(String args[]) 
    { 
        TreeSet t = new TreeSet();
        t.add("3");
        t.add("9");
        t.add("1");
        t.add("4");
        t.add("8"); 
        System.out.println(t);
    }
}

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Q108

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.fill(array, 1, 4, 8);
        for (int i = 0; i < 5 ; i++)
            System.out.print(array[i]);
    }
}

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Q109

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));
        obj.clear();
        System.out.print(obj.size());
    }
}

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Q110

Which of these methods is used to retrieve the elements in properties object at specific location?

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Q111

Which of these is true about unmodifiableCollection() method?

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Q112

What will be the output of the following Java code?

import java.lang.reflect.*;
class Additional_packages 
{	 
     public static void main(String args[]) 
     {
   try 
         {
       Class c = Class.forName("java.awt.Dimension");
 Constructor constructors[] = c.getConstructors();
 for (int i = 0; i < constructors.length; i++)
     System.out.println(constructors[i]);
   }
   catch (Exception e)
         {
         System.out.print("Exception");
         }
    }
}

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Q113

Which of these method is used add an element and corresponding key to a map?

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Q114

How to remove duplicates from List?

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Q115

Which of these iterators can be used only with List?

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Q116

Is hashmap an ordered collection.

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Q117

How is Arrays.asList() different than the standard way of initialising List?

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Q118

What is difference between dequeue() and peek() function of java?

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Q119

What is Remote method invocation (RMI)?

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Q120

Which of these method of ArrayList class is used to obtain present size of an object?

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