Java interview programs - Part2

1.Find Maximum and Minium number in the given array.
public class ArrayMinMax {

public static void main(String[] args) {

int numbers[] = { 7, 4, 9, 1, 3, 8, 6 };
int max = numbers[0];
for (int i = 0; i < numbers.length; i++) {
if (max < numbers[i]) {
max = numbers[i];
}
}
System.out.println("max number is " + max);

int min = numbers[0];
for (int i = 0; i < numbers.length; i++) {
if (min > numbers[i]) {
min = numbers[i];
}
}
System.out.println("min number is " + min);

}

}

Output:

max number is 9

min number is 1

2.Sorting the numbers using bubble sort algorithm

public class BubbleSort {

public static void main(String[] args) {

int numbers[] = { 7, 4, 9, 1, 3, 8, 6 };

for (int i = 0; i < numbers.length; i++) {

for (int j = 1; j < (numbers.length - i); j++) {

if (numbers[j - 1] > numbers[j]) {

int temp = numbers[j];

numbers[j] = numbers[j - 1];

numbers[j - 1] = temp;

}

}

}

for (int i = 0; i < numbers.length; i++)

System.out.print(numbers[i] + " ");

}

}

Output:

1 3 4 6 7 8 9 

3.Find factorial of a given number

public class Factorial {

public static void main(String args[]) {

int n = 6;

int fact = 1;

for (int i = 2; i <= n; i++) {

fact = fact * i;

}

System.out.println("The factorial value is " + fact);

}

}

Output:

The factorial value is 720

4.Find Fibonacci series upto given count.

public class Fibonacci {

public static void main(String args[]) {

int f0 = 0, f1 = 1, f2 = 1;

int count = 10;

int i = 0;

System.out.print(f0 + " " + f1 + " " + f2);

while (i <= count) {

f0 = f1;

f1 = f2;

f2 = f0 + f1;

System.out.print(" " + f2);

i++;

}

}

}

Output:

0 1 1 2 3 5 8 13 21 34 55 89 144 233

5.Swap two numbers without using 3rd variable

public class Swap {

public static void main(String args[]) {

int a = 30;

int b = 40;

a = a + b;

b = a - b;

a = a - b;

System.out.println(a + "  " + b);

}

}

Output:

40  30

6.TypeCasting program

public class TypeCasting {

public static void main(String[] args) {

int a = 10;

// A data type of lower size is assigned to a data type of higher size

double b = a; // Implicit type casting.

System.out.println(b); // 10.0

// byte –> short –> int –> long –> float –> double

double c = 10.2;

int d = (int) c; // Explicit type casting

System.out.println(d); // 10

long e = 20;

float f = e; // Implicit type casting.

System.out.println(f);

boolean m = true;

// int n = (int) m; // boolean is incompatible for conversion

boolean o = m;

System.out.println(o); // true

float x = 10.2f;

if (x == 10.2) {

System.out.println("same");

}

if (x == 10.2f) {

System.out.println("now float same");

}

double y = 10.2;

if (y == 10.2) {

System.out.println("double same");

}

}

}

Output:

10.0

10

20.0

true

now float same

double same

7.Read text file
package javaprograms;

import java.io.BufferedReader;
import java.io.FileReader;

public class ReadFile {

public static void main(String args[]) throws Exception {
FileReader file = new FileReader("E:\\Selenium\\testFile.txt");
BufferedReader buffered = new BufferedReader(file);
String str;
while((str=buffered.readLine())!=null) {
System.out.println(str);
}
buffered.close();
}

}

Output:

janardhan

bhaskar

8.Reverse Char Array :

public class ReverseString {

public static void main(String[] args) {
char[] var = {'h','e','l','l','o'};
char ch;
for(int i=var.length-1,j=0;j<var.length/2;i--,j++) {
ch=var[i];
var[i] = var[j];
var[j]= ch;
}

for(char c : var) {
System.out.print(c);
}
System.out.println();

for(int k=0;k<var.length;k++) {
System.out.print(var[k]);
}
}


}

Output:

olleh

olleh

9.Try,Catch/Finally :

a.
public class TryCatch {

public void tryCatchArithmeticWrongException() {
try {
int a = 5/0;
System.out.println("This should require either catch/finally");
}
catch(ArrayIndexOutOfBoundsException e) {
System.out.println(e);
}
System.out.println("this will not execute");
}

public void tryCatchAnyType() {
try {
int a = 5/0;
System.out.println("This should require either catch/finally");
}
catch(Exception e) {
System.out.println(e);
}
System.out.println("this will execute");
}

public void tryCatchArithmetic() {
try {
int a = 5/0;
System.out.println("This should require either catch/finally");
}
catch(ArithmeticException e) {
System.out.println(e);
}
System.out.println("this will execute");
}

public static void main(String[] args) {
TryCatch obj = new TryCatch();
// obj.tryCatchArithmetic();
// obj.tryCatchAnyType();  // Then this also will not execute
obj.tryCatchAnyType();
obj.tryCatchArithmetic();
obj.tryCatchArithmeticWrongException();

}


}

Output:

java.lang.ArithmeticException: / by zero

this will execute

java.lang.ArithmeticException: / by zero

this will execute

Exception in thread "main" java.lang.ArithmeticException: / by zero

at TryCatch.tryCatchArithmeticWrongException(TryCatch.java:5)

at TryCatch.main(TryCatch.java:42)

b.Try/Catch/Finally return types :

public class TryCatchFinally {

public static int divideone(int a) {

try {

int b=8/a;

System.out.println("this is try block "+b);

return 10;

}

catch(Exception e) {

System.out.println("this is catch block");

return 20;

}

finally {

System.out.println("this is in finally block");

   return 30;

}

}

public static int dividetwo(int a) {

try {

int b=8/a;

System.out.println("this is try block "+b);

return 10;

}

catch(Exception e) {

System.out.println("this is catch block");

return 20;

}

finally {

System.out.println("this is in finally block");

  // return 30;

}

// return a;  // gives error, since we already mentioned return in try block.

}

public static void main(String[] args) {

int value1 = TryCatchFinally.divideone(5);

System.out.println(value1);

TryCatchFinally.divideone(0);

System.out.println(value1);

int value2 = TryCatchFinally.dividetwo(5);

System.out.println(value2);

TryCatchFinally.dividetwo(0);

System.out.println(value2);

}

}

Output:

this is try block 1

this is in finally block

30

this is catch block

this is in finally block

30

this is try block 1

this is in finally block

10

this is catch block

this is in finally block

10

10.Difference between List and Set :

import java.util.ArrayList;
import java.util.HashSet;
import java.util.List;
import java.util.Set;


public class ListSet {


public static void main(String[] args) {

System.out.println("List Example");
// List<String> list = new List<String> // List is an interface.
List<String> list = new ArrayList<String>();
list.add("gitam");
list.add("college");
list.add("of");
list.add("engineering");
for(String value : list) {
System.out.print(value+" ");
}

System.out.println("\nSet Example");
Set<String> set = new HashSet<String>();
set.add("gitam");
set.add("college");
set.add("of");
set.add("engineering");
for(String value : set) {
System.out.print(value+" ");
}

System.out.println("List Allows duplicates Example");
// List<String> list = new List<String> // List is an interface.
List<String> duplicates = new ArrayList<String>();
duplicates.add("10");
duplicates.add("20");
duplicates.add("30");
duplicates.add("10");
for(String value : duplicates) {
System.out.print(value+" ");
}

System.out.println("The size of the list now is 3 or 4 : " + duplicates.size());

System.out.println("\nSet Does not allow duplicates Example");
Set<String> noduplicates = new HashSet<String>();
noduplicates.add("10");
noduplicates.add("20");
noduplicates.add("30");
noduplicates.add("10");
for(String value : noduplicates) {
System.out.print(value+" ");
}

System.out.println("The size of the set now is 3 or 4 : " + noduplicates.size());
}

}

Output:
List Example
gitam college of engineering
Set Example
of gitam college engineering List Allows duplicates Example
10 20 30 10 The size of the list now is 3 or 4 : 4

Set Does not allow duplicates Example
20 10 30 The size of the set now is 3 or 4 : 3