Assessment Java Programming Skills

What will be the output of the following code

import java.util.Arrays;

import java.util.Comparator;

public class ComparatorTest {

public static void main(String args[]){

String[] ar= {“c”,”d”,”b”,”a”,”e”};

InnerClass in=new InnerClass();

Arrays.parallelSort(ar, in);

for(String str : ar)

System.out.println(str +””);

System.out.println(Arrays.binarySearch(ar, “b”));

}

static class InnerClass implements Comparator<String>{

public int compare(String s1, String s2){

return s2.compareTo(s1);

}

}

}

• e d c b a -1

• a b c 0 e d

• d b c e a 1

• e b a d c

What will be the output of the following code

import java.util.LinkedHashSet;

import java.util.Set;

public class LinkedHashSetTest {

public static void main (String args[]){

Set s=new LinkedHashSet();

s.add(“1”);s.add(1);

s.add(3);

s.add(2);

System.out.println(s);

}

}

• [1, 1, 2, 3]

• [1, 2, 2 3[

• [1, 1, 3, 2]

• [1, 2, 3]

What will be the output of the following code

import java.util.ArrayList;

import java.util.List;

public class ListDemo {

public static void main (String args[]) {

List<Integer> list=new ArrayList<Integer>();

list.add(2); list.add(3); m(list);

public static void m(List<Number> list) {

System.out.println(list);

}

}

}

• 3

• 3.0

• Compile time exception

• Runtime exception

Which of those doesn’t have an index based structure?

• List

• Set

• Map

• Vector

java.util.Collections is a:

• Class

• Interface

• Object

• None of the above

In Iterator, hasMoreElements() method of Enumeration has been changed to:

• hasNextElement()

• isNext()

• hasNext()

• name remains same

What of the following is the default value of a local variable?

• null

• 0

• Depends upon the type of variable

• Not assigned

Which of the following is true about public access modifier?

• Variables, methods and constructors which are declared public can be accessed by any class.

• Variables, methods and constructors which are declared public can be accessed by any class lying in same package.

• Variables, methods and constructors which are declared public in the superclass can be accessed only by its child class.

• None of the above.

What is class variable?

• class variables are static variables within a class but outside any method.

• class variables are variables defined inside methods, constructors or blocks.

• class variables are variables within a class but outside any method.

• None of the above.

Which of the following is correct about default methods?

• With java 8, an interface can have default implementation of a function in interfaces.

• An interface can also have static helper methods from Java 8 onwards.

• Both of the above.

• None of the above.