InstanceOfJava

How to find Biggest Substring in between specified character or String

Posted by: Instanceofjava Posted date: 1:23 PM / comment : 3 Core java Interview Questions , Java Programs

1. Java Program to find biggest substring in between specified character or string

String: i am rajesh kumar ravi

in between: 'a'

package com.instaceofjava;
public class BiggestSubString{
public static void main(String[] args) {
String str="i am rajesh kumar ravi";
String longest="";
int maxlength=0;
String arr[]=str.split("a");
for (int i = 1; i < arr.length-1; i++) {
System.out.println(arr[i]); // printing substrings
if(arr[i].length() > maxlength){
maxlength = arr[i].length();
longest = arr[i];
}
}
System.out.println("Longest substring is: "+longest);
}
}

Output:

m r
jesh kum
r r
Longest substring is: jesh kum

Java Basic Interview Programming Questions on Constructors

Posted by: Instanceofjava Posted date: 1:01 PM / comment : 6 Core java Interview Questions , Java Programs

Below programs are the basic programs frequently asking in java quizzes try to test your java programming skills by answering the questions. if you are having any doubts feel free to ask us.
Java Coding Questions on constructors.

1.What will be the Output of this program.

public class Test1{
Test1(int i){
System.out.println("Test1 Constructor "+i);
}
}

public class Test2{
Test1 t1= new Test1(10);
Test2(int i){
System.out.println("Test2 Constructor "+i);
}
public static void main(String[] args) {
Test2 t2= new Test2(5);
}
}

2.What will be the Output of this program.

public class A{
A(){
System.out.println("A Class Constructor ");
}
}

public class B extends A{
B(){
System.out.println("B Class Constructor ");
}
public static void main(String[] args) {
B ob= new B();
}
}

3.What will be the Output of this program.

public class A{
A(){
this(0);
System.out.println("Hi ");
}
A(int x){
this(0,0);
System.out.println("Hello");
}
A(int x, int y){
System.out.println("How are you");
}
public static void main(String[] args) {
A ob= new A();
}
}

Please Respond If you know about any Opportunity

Posted by: Instanceofjava Posted date: 1:06 PM / comment : 0 jobs

Hi Friends.

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Please let us know if you have any openings in your company or your friends company so that we can help lot of people who are really talented and waiting for an opportunity.

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Send your updated profile to us at Instanceofjava@gmail.com
please mention your preferred location in subject.

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Bubble sort algorithm in java with example

Posted by: Instanceofjava Posted date: 5:30 PM / comment : 0 Java Programs , Sorting algorithms

Java Program to sort array using bubble sort

package com.instaceofjava;
public class BubbleSortExample{
int[] array={4,2,5,6,9,1};
int n = array.length;
int k;
for (int m = n; m>= 0; m--) {
for (int j = 0; j < n-1; j++) {
k = j + 1;
if (array[j] > array[k]) {
int temp;
temp = array[j];
array[j] = array[k];
array[k] = temp;
}
}
for (int x = 0; x < array.length; x++) {
System.out.print(array[x] + ", ");
}
System.out.println();
}
}
}

Output:

2, 4, 5, 6, 1, 9,
2, 4, 5, 1, 6, 9,
2, 4, 1, 5, 6, 9,
2, 1, 4, 5, 6, 9,
1, 2, 4, 5, 6, 9,
1, 2, 4, 5, 6, 9,
1, 2, 4, 5, 6, 9,

AtomicInteger in Java

Posted by: Instanceofjava Posted date: 5:49 PM / comment : 0 Java Programs

Java.util.concurrent.atomic package provides very useful classes that support lock free and thread safe programming.
The main use of this class is an int value that may be updated automatically.
AtomicInteger has some useful methods. Before that lets see the some points about this class.
Commonly we will use this AtomicInteger to handle the counter that is accessible by different threads simultaneously.

Java.util.concurrent.atomic.AtomicInteger:

public class AtomicInteger
extends Number
implements Serializable

AtomicInteger Class Constructors:

public AtomicInteger(): Creates a new AtomicInteger object with default value 0.

AtomicInteger atomicInteger = new AtomicInteger();

public AtomicInteger(int initialValue): Creates a new AtomicInteger object with given initial value.

AtomicInteger atomicInteger = new AtomicInteger(10);

AtomicInteger Class Methods:

1.public final void set(int newValue):

Sets given value to the object.

Java Program to create AtomicInteger class object and sets some value.

package com.instaceofjava;
import java.util.concurrent.atomic.AtomicInteger;
public class AtomicIntegerExample{
public static void main(String[] args) {
AtomicInteger atomicInteger = new AtomicInteger();
System.out.println(atomicInteger);
atomicInteger.set(10);
System.out.println(atomicInteger);
}
}

Output:

2, public final void get():

Used to get current value.

Java Program to create AtomicInteger class object and sets some value and get.

package com.instaceofjava;
import java.util.concurrent.atomic.AtomicInteger;
public class AtomicIntegerExample{
public static void main(String[] args) {
AtomicInteger atomicInteger = new AtomicInteger();
System.out.println(atomicInteger.get());
atomicInteger.set(10);
System.out.println(atomicInteger.get());
}
}

Output:

3.public final int getAndSet(int newValue):

Automatically sets the given value and returns old value.

Java Program which explains getAndSet(int x) method of AtomicInteger class

package com.instaceofjava;
import java.util.concurrent.atomic.AtomicInteger;
public class AtomicIntegerExample{
public static void main(String[] args) {
AtomicInteger atomicInteger = new AtomicInteger();
System.out.println(atomicInteger.get());
atomicInteger.set(10);
System.out.println(atomicInteger.get());
System.out.println(atomicInteger.getAndSet(12));
System.out.println(atomicInteger.get());
}
}

Output:

4.public final int incrementAndGet()

Automatically increments the value one and returns updated value

Java Program which explains incrementAndGet() method of AtomicInteger class

package com.instaceofjava;
import java.util.concurrent.atomic.AtomicInteger;
public class AtomicIntegerExample{
public static void main(String[] args) {
AtomicInteger atomicInteger = new AtomicInteger();
System.out.println(atomicInteger.get());
atomicInteger.set(10);
System.out.println(atomicInteger.get());
System.out.println(atomicInteger.incrementAndGet());
}
}

Output:

How to create immutable class in java

Posted by: Instanceofjava Posted date: 11:11 PM / comment : 0 Java Programs

In Java String and all wrapper classes are immutable classes.
So how to create custom immutable class in java?
Lets see how to make a class object immutable.

Immutable class:

Make class final so that it should not be inherited.
All the variables should be private so should not be accessible outside of class.
Make all variables final so that value can not be changed.
A constructor to assign values to variables in class.
Do not add any setter methods.

1. Java Program to create custom immutable class object in java.

package com.instaceofjava;
public final class ImmutableClass{
private final int a;
private final int b;
ImmutableClass( int x, int y){
a=x;
b=y;
}
public getA(){
return a;
}
public getB(){
return b;
}
public static void main(String[] args) {
ImmutableClass obj= new ImmutableClass(10,20);
System.out.println("a="+obj.getA());
System.out.println("b="+obj.getB());
}
}

Output:

a=10
b=20

String class in java: Immutable

public final class String
implements java.io.Serializable, Comparable<String>, CharSequence
{
//String class variables
private final char value[];
private final int offset;
private final int count;
private int hash; // Default to 0
private static final ObjectStreamField[] serialPersistentFields =
new ObjectStreamField[0];
//String class constructor
public String(String original) {
int size = original.count;
char[] originalValue = original.value;
char[] v;
if (originalValue.length > size) {
// The array representing the String is bigger than the new
// String itself. Perhaps this constructor is being called
// in order to trim the baggage, so make a copy of the array.
int off = original.offset;
v = Arrays.copyOfRange(originalValue, off, off+size);
} else {
// The array representing the String is the same
// size as the String, so no point in making a copy.
v = originalValue;
}
this.offset = 0;
this.count = size;
this.value = v;
}
}

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