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

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???

Can you please mention the problem statement or problem code.

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”))

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

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.

//