Java Interview Coding Questions:

1) How To Reverse a String without using reverse method:

    public class Reverse{

    public static void main(String[] args) {

        String str = "STRING";

        char []chr = str.toCharArray();

        for(int i=chr.length-1; i>=0; i--) {

            System.out.print(chr[i]);

        }

       

    }

}

 

2) Swap two numbers without using third variable: 

public class Swap {

   

    public static void main(String[] args) {

        int a = 11;

        int b = 12;

        //logic

        b = b-a;

        a = a+b;

        b = a-b;

        System.out.println("value of a is "+a);

        System.out.println("value of b is "+b);

    }

}

3) To check if vowel is present in the string:

public class Vowel {

    public static void main(String[] args) {

        char chr[] = {'a','e','i','o','u'};

        String str = "HimanshuU";

        char stchr[] = str.toLowerCase().toCharArray();

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

            for(int j=0; j<chr.length; j++) {

                if(stchr[i]==chr[j]) {

                    System.out.println(stchr[i]);

                }

            }

        }

    }

}

 

4) Program to use the linked list without collection class:

public class linkedlist

{

    public static class Node         //We are defining a node  here

    {

        int data;       //data of node here

        Node next;      //next refers to the address of the next node

       

    }

    public static void main(String args[])

    {

        Node newnode1=new Node();    //here we are making objects of class Node

        Node newnode2=new Node();    //basically these are nodes of first linkedlist

        Node newnode3=new Node();    

        Node newnode4=new Node();    

        newnode1.data=1;

        newnode2.data=2;

        newnode3.data=3;

        newnode4.data=4;

         

         

        newnode1.next=newnode2;       //here we are linking the previous node to the next node of the list

        newnode2.next=newnode3;

        newnode3.next=newnode4;

        newnode4.next=null;

        //Now we will print the linked list

       for (int i=1;i<=4;i++)

        {

            System.out.print(newnode1.data+" ");

            newnode1=newnode1.next;       //we are assigning the next address of the linked list to the current address

        }

    }

}