Initializing a string in java error

Question

While running this code on netbeans it always run the if statement block but on compiling it on HackerRank code editor it always go into the else statement . Help me with the error.

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.util.Scanner;


class Person {

public static void main(String[] args) throws Exception{
    Scanner sc=new Scanner(System.in);
    BufferedReader sb=new BufferedReader(new InputStreamReader(System.in));
    int T=sc.nextInt();
    for(int j=0;j<T;j++)
        {String s="";
         s=sb.readLine();
         StringBuffer even=new StringBuffer();
         StringBuffer odd=new StringBuffer();
         if(s!=null)
         {for(int i=0;i<s.length();i++)
         {
             if(i%2==0)
                 even.append(s.charAt(i));
             else
                 odd.append(s.charAt(i));
         }

        System.out.println(even+" "+odd);
        }
         else
             System.out.println("Enter some input");
        }
   }
 }

Answer 1

Why are you using both scanner and bufferedreader ? Try the next() method from the scanner instead

s=sc.next();

If you want to make use of bufferedreader then try these two statements instead.

int T=Integer.parseInt(sb.readLine());
for(int j=0;j<T;j++)
{
    String s=sb.readLine();

Once if you make both the scanner and bufferedreader listen to input from the inputstream, How will the bufferedreader know till where the input has been read? (But the scanner knows it) That's why it returns null instead. I hope you understood it.

To keep it simple, just use either the scanner or the bufferedreader not both.