## Saturday, April 27, 2019

### Java Program Coding Interview Questions

Q- How to sort array using single loop in java?

Q- How to count duplicate elements in array in java? or How to find duplicate values in array in java?

```
package com.array.example;
import java.util.Arrays;

public class ArrayElementCount {

public static void main(String[] args) {

int b[] = { 1, 1, 1, 2, 2, 3, 4, 3, 5, 4, 5, 5, 5 };
Arrays.sort(b);
int count = 1;
int temp = 0;
for (int j = 0; j < b.length; j++) {
if (j + 1 < b.length) {
temp = b[j + 1];
}
if (b[j] == temp) {
count++;
} else {
System.out.println("Element :" + b[j] + " Count:" + count);
count = 1;
}
if (j == b.length - 1) {
System.out.println("Element :" + b[j] + " Count:" + count);
}
}
}
}
```
Output:
```Element :1 Count:3
Element :2 Count:2
Element :3 Count:2
Element :4 Count:2
Element :5 Count:5
```

Q- Write a program for conversion of a decimal number to binary number.

```package com.shubh.example;

public class DecimalToBinaryExample {
public static void main(String[] args) {
int number = 25;
DecimalToBinaryExample.decimalToBinary(number);
}

private static void decimalToBinary(int n) {
int a;
System.out.println("Decimal number: " + n);
String x = "";
while (n > 0) {
a = n % 2;
x = x + "" + a;
n = n / 2;
}
System.out.println("Binary number:" + x);
}
}
```
Output:
```
Decimal number: 25
Binary number:10011
```
Q- What is the output of below program?
```
package com.shubh.example;

public class PrintPerson {

public static void main(String[] args) {
PrintPerson instance = new PrintPerson();
Person person = instance.new Person();
person.setName("In Main Block");
System.out.println(person.getName());
instance.pouplatePerson(person);
}

public void pouplatePerson(Person person) {
person = new Person();
person.setName("In pouplatePerson");
System.out.println(person.getName());
}

class Person {
String name;

public String getName() {
return name;
}

public void setName(String name) {
this.name = name;
}
}
}
```
Output:
```
In Main Block
In pouplatePerson
```

Q- How to sort array in java without using sort method? or How to sort array in java without using collections?

Q- How to eliminate duplicate values from array in java without using collections? or How to remove duplicates from array in Java without using collections?

Q- How to Shuffle an Array or a List?

Shuffle an Array or List with the Collections.
We can use Collections.shuffle(list) to shuffle a list. And Collections.shuffle(Arrays.asList(a))  to shuffle an array.

Q- How to shuffle an Array or ArrayList without collections?
Ansewr :- Shuffle Array or ArrayList Without Using Collections Example

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