what is the problem with code??????? Why is null coming in the output??

general
1

import java.io.;
import java.util.;
import java.math.*;
class Test
{
public static void main(String args[])throws IOException
{
BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
int N, T,i,j,k=0;
int ck=0,s=0,e=0,em=0,m=0,mh=0,h=0;
String[] con= {“cakewalk”,“simple”,“easy”,“easy-medium”,“medium”,“medium-hard”,“hard”};
String[] result=new String[10];
T=Integer.parseInt(br.readLine());
Random rn=new Random();
for(i=1;i<=T;i++)
{
N=Integer.parseInt(br.readLine());
for(j=1;j<=N;j++)
{
int index = rn.nextInt(con.length);
String con1=con[index];
System.out.println(con[index]);

        if (con1 == "cakewalk")
        {
            ++ck;
        }
         else if(con1 == "simple")
    {
      ++s;
    }
    else if(con1=="easy")
    {
      ++e;
    }
    else if(con1=="easy-medium")
    {
      ++em;
    }
    else if(con1=="medium")
    {
      ++m;
    }
    else if(con1=="medium-hard")
    {
      ++mh;
    }
    else if(con1=="hard")
    {
      ++h;
    }
    //System.out.println(ck+""+s+""+e+""+em+""+m+""+mh+""+h);

  }
        if((ck!=0&& s!=0 && e!=0 && em!=0 && m!=0 && mh!=0 && h!=0)||(ck!=0 && s!=0 && e!=0 && em!=0 && mh!=0 && h!=0)||(ck!=0 && s!=0 && e!=0 && m!=0 && mh!=0 && h!=0)||(ck!=0 && s!=0 && e!=0 && em!=0 && m!=0 && h!=0)||(ck!=0 && s!=0 && e!=0 && em!=0 && m!=0 && mh!=0))
        {
            result[k]="Yes";
            k++;
        }
        else
        {
            result[k]="No";
            k++;
        }
        for(i=0;i<result.length;i++)
        {
            System.out.println(result[i]);
        }

}

}

}

Output:-
1
7
easy-medium
easy-medium
hard
simple
easy-medium
medium-hard
hard
No
null
null
null
null
null
null
null
null
null

Want to know why is null coming in the code???

2

Can you please mention the problem statement or problem code.

3

In Java You cannot compare two strings using this a==b

You have used if (con1 == “cakewalk”)

But you should use if(con1.equals(“cakewalk”))

4

It is the first problem given under Beginner section (Problem Code: C00K0FF).

5

https://pastebin.com/KhUsguxk

Above is the link to my code and output.
As you may have seen the code works but in the output there are 3 test cases
According to the question there should be 1 cakewalk 1 easy and 1 simple in each test case to print YES
But in the third case there is YES printed where all the above things aren’t present.