Question 1.

Which of the following are valid Java Keywords

A. goto

B. final

C. NULL

D.finally

E. extend

F. main

Ans : goto, final, finally

Question 2.

True / False. Select if True
A. Instance variables are always initiated to defaults //True

B. Local variables are always initiated to defaults //False

C. Array Elements are always initiated to defaults //True

D. Object references that are not initialized
explicitly will have their value set to null always //False

Question 3.

Select all the following statements about ‘wait’ method that are true

A. wait() is static final method that cannot be overrided.

B. wait() is an instance method of object class.

C. wait() is an instance method of Thread class.

D.Thread must have lock an the object involved to call
wait().

Ans : B & D

Question 4.

Select the code segments(assuming is part of valid class) below that compile and run correctly with output: We are Equal

A. int i = 10;

long l = 10L;
if( i == l )
System.out.println(“We are Equal”); //Equal

B. int i = 10;
Integer ii = new Integer(10);
if( i == ii)
System.out.println(“We are Equal”); //Equal

C. int i = 10; char c = 10;
if( c == i)
System.out.println(“We are Equal”); //Equal

D. Integer ii = new Integer(10);
Integer jj = new Integer(10);
if(ii == jj)
System.out.println(“We are Equal”); //Not Equal

E. String s1 = “Null”;
String s2 = “Null”;
if( s1 == s2)
System.out.println(“We are Equal”); //Equal

F. String s1 = “Null”;
String s2 = new String(s1);
if( s1 == s2)
System.out.println(“We are Equal”); //Not Equal

Question 5.

Which of the following are true about overloading & overridding.

A. Overrided methods return different return types and

will be in different classes. //False

B. Overloaded methods supplement where as overridden
method replace the method it overrides. //True

C. Return type of overriden method must be identical to
return type of method it overrides. //True

D. Given a method
public void aMethod(int i,float f);
the method
public void aMethod(float f,int i);
is a possible overridden method. //False

Question 6.

Which of the follwing is true about static modifier.

A. static can be applied to : instance variables, methods,

code Segments and classes. //True

B. a static method cannot be overridden. //True

C. inner classes can be both static & private. //True

D. a static reference cannot be made through non static
method or code block. //True

E. abstract & static both can be applied together to a
method. //False

Question 7.

When can we use same method name in java for two different methods

A. If the two methods are in two unrelated clasess. //False

B. If the two methods are in the same class and they
differ in argument & return type. //True

C. If one method is in base class, other is in its sub
class and the two mehtods differ only in return type. //False

D. If one method is in base class, other is in its sub class
and the two mehtods differ both arguments list and in
return type. //True

Question 8.

Given the code, what is the output

public class demo{
static int i = 10;
public static void main(String[] arg){
static int i = 20;
System.out.println(“i is :”+i);
}
}

A. Code Does’t Compile. //True

B. Code Compiles but error will be generated at runtime.

C. Code Compiles & runs, output is
i is : 10

D. Code compiles & runs, output is
i is : 20

Question 9.

public class demo
{
public static void main(String[] args)
{
int i = 10;
int j = 10;
boolean b = false;

if( b = i == j)
System.out.println(“True”);
else
System.out.println(“False”);
}
}

Ans : True

Question 10.

class demo
{
public static void main(String []args)
{
Byte b1 = new Byte(“127”);
if(b1.toString() == b1.toString())
System.out.println(“True”);
else
System.out.println(“False”);
}
}

Ans : False

Even character replacing with alphabet number and Vowels replace with alphabet numbers

import java.util.Scanner;
public class demo {
public static void main(String[] args) {

Scanner sc = new Scanner(System.in);
System.out.print(“Enter your string: “);
String even_odd = sc.next();

System.out.println(“Even character replacing with alphabet number”);
for(int i = 0; i<even_odd.length(); i++){
if(i%2==0){
System.out.print(even_odd.charAt(i));
} else if(i%2==1){
//System.out.print(even_odd.charAt(i));
String str = Character.toString(even_odd.charAt(i));
String input=str.toLowerCase();
String alphabet=”abcdefghijklmnopqrstuvwxyz”;
for(int j=0; j<input.length();j++){
System.out.print(alphabet.indexOf(input.charAt(j))+1);
}

}
}
System.out.println();
System.out.println(“Vowels replace with alphabet numbers”);
for(int i=0;i <even_odd.length();i++){
if((even_odd.charAt(i) == ‘a’) || (even_odd.charAt(i) == ‘e’) ||
(even_odd.charAt(i) == ‘i’) || (even_odd.charAt(i) == ‘o’) ||
(even_odd.charAt(i) == ‘u’)) {
String str = Character.toString(even_odd.charAt(i));
String input=str.toLowerCase();
String alphabet=”abcdefghijklmnopqrstuvwxyz”;
for(int j=0; j<input.length();j++){
System.out.print(alphabet.indexOf(input.charAt(j))+1);
}
//System.out.print(even_odd.charAt(i));
} else { System.out.print(even_odd.charAt(i)); }
}

}
}

Reverse string without reverse function

1.public class demo
{
public static void main(String args[])
{
String s=”arun kumar”;
StringBuilder sb=new StringBuilder();
for(int i=s.length()-1; i>=0; i++)
sb.append(s.charAt(i));

}
}

2.

public class reverse
{
public static void main(String args[])
{
one r=new one();
}
}
class one
{
public String reverse(String sentence)
{
String reverse = “i am udhaya”;
char [] s = sentence.toCharArray();
int first = s.length-1;
int last = s.length-1;
String temp = “”;

for(int i = s.length-1; i>=0; i–)
{
temp = ” “;
while(s[first] != ‘ ‘)
{
System.out.println(s[first]);
first–;

}
while(last != first)
{
temp = s[last] + temp;
last–;
i–;
}
reverse = reverse + temp;
}
return reverse;
}
}

3.

import java.util.ArrayList;

public class Reverser
{
public static void main(String args[])
{
String myName = “Here we go”;
ArrayList al = new ArrayList();
al = recursiveMethod(myName,al);
al.trimToSize();
StringBuilder sb = new StringBuilder();

for(int i = al.size()-1; i>=0;i–)
{
sb.append(al.get(i)+” “);

}
System.out.println(sb);

}
public static ArrayList recursiveMethod(String myName,ArrayList al)
{

int index = myName.indexOf(” “);
al.add(myName.substring(0, index));
myName = myName.substring(index+1);
if(myName.indexOf(” “)==-1)
{
al.add(myName.substring(0));
return al;
}
return recursiveMethod(myName,al);

}
}

Input in int output in string
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

public class one {
public static void main(String[] args) throws IOException {
BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
int i=Integer.parseInt(br.readLine());
if(i==1)
{
System.out.println(“one”);
}
else if(i==2)
{
System.out.println(“two”);
}
else if(i==3)
{
System.out.println(“three”);
}
else if(i==4)
{
System.out.println(“four”);
}
else if(i==5)
{
System.out.println(“five”);
}
else if(i==6)
{
System.out.println(“six”);
}
else if(i==7)
{
System.out.println(“seven”);
}
else if(i==8)
{
System.out.println(“eight”);
}
else if(i==9)
{
System.out.println(“nine”);
}
else if(i==10)
{
System.out.println(“ten”);
}
else if(i>10)
{
System.out.println(“Enter valid option”);
}
else
{
System.out.println(“process over”);
}
}

}