JAVA INTERVIEW PROGRAMS

duplicate string remover without using string method

 TreeSet<String>a=new TreeSet<String>();

a.add("a");
a.add("b");
a.add("d");
a.add("b");
a.add("d");
a.add("b");
a.add("b");


Iterator<String>t=a.iterator();

while(t.hasNext())
{
System.out.print(t.next());
}

duplicate String Finder  or Repating string character


  String t="BBbbnNNaill";
Multiset<Character>d=HashMultiset.create();
for(int i=0;i<t.length();i++)
   {
d.add(t.toLowerCase().charAt(i));
   }
for(Character ch:d.elementSet())
   {
System.out.println(ch+"----"+d.count(ch));
   }



repeating array INDEX(Number)using (Multiset)

int data[]={3,5,5,6,6,6,9}; Multiset<Integer>d=HashMultiset.create(); for(int i=0;i<data.length;i++) { d.add(data[i]); } for(Integer i:d.elementSet()) { System.out.println(i+"-------"+d.count(i)); }


Duplicate array Remover using for loop


String str[]={"3","2","3","2","1"}; for(int i=0;i<str.length-2;i++) { for(int j=i+1;j<str.length;j++) { if(str[i].equals(str[j])) { str[j]=""; } } } for(String s:str) { System.out.println(s); } }




Sort array  INDEX  using (Arrays)

   int  data[]={2,6,7,8,9};
Arrays.sort(data);
for(int c:data)
{
System.out.println(c);

}


Sort array  INDEX using --for loop



  int arr[]={20,40,50,30,10};
int temp=0;
for(int i=0;i<=(arr.length)-1;i++)
{
for(int j=0;j<=(arr.length)-1;j++)
{
if(arr[i]<arr[j])
{
temp=arr[j];
arr[j]=arr[i];
arr[i]=temp;
System.out.println("hh"+arr[j]);
}
}
}

for(int i=0;i<=(arr.length)-1;i++)
{

//for displaying the sorted array
System.out.println(arr[i]);
}

}



Sort String-- using (Arrays)

String data1[]={"b","c","j","a","d"}; Arrays.sort(data1); for(String c:data1) { System.out.println(c); }



//fibonaaci series int l=0; int j=1; for(int i=0;i<=5;i++) { l=l+j; j=l-j; System.out.println(l); }

//palindrom String t11="MAdam"; String nw=new StringBuilder(t11).reverse().toString(); if(t11.equals(nw)) { System.out.println("palidrom"); } else { System.out.println("NoT a Palindrom"); }

String Reverse (how is she - she is how)

String str = "He is the one"; String temp = ""; String finalString = ""; for(int i =str.length()-1;i>=0;i--){ temp +=i!=0?str.charAt(i):str.charAt(i)+" "; if(str.charAt(i) == ' '||i==0){ for(int j=temp.length()-1;j>=0;j--){ finalString += temp.charAt(j); } temp = ""; } } System.out.println(finalString);

SingleTon class example program

rules of singleton class

1.private constructor should be thr
2.static method should be thr
3.It returns an object which is already created


class singleton()
{
private Static singleton single=null;

//private constructor
private singleton()
{

}

//static method
public static singletongetInstance()
{
if(single==null)
{
single=new single();
}

//return obj which is created above same colour
return single;
}
}




Method over loading ......

 class test
  {
   public void A(char s)
   {
    System.out.println(s);
   }
   public void A(char s,int c)
   {
    System.out.println(c+"  "+s);
   }

  }
  class main
  {
   public static void main(String[] args)
   {
    test tt=new test();
    tt.A("arun");
    tt.A("arun", 10);
   }
  }

Method Override

class qpsider

{
   public void A()
   {
      System.out.println("Selenium");
   }
}
class java extends qspider

{
   public void A()

    {
      System.out.println("Webdriver");
    }
   public static void main( String args[])

   {
      java obj = new java();
      obj.eat();
   }
}

Upcasting



class Bike
{
void run()
{
System.out.println("running");} }
class Splender extends Bike
{ void run()
{
System.out.println("running safely with 60km");
} public static void main(String args[])

{  //upcasting
Bike b = new Splender(); b.run(); } }