import java.util.Scanner;
public class Sum{
  public static void main(String args[]){
    Scanner sc= new Scanner(System.in);
    int N, sum=0;
    System.out.print("Enter the value of N:");
    N= sc.nextInt();
    if(N<10000){
      if(N<0){
        for(int x=N; x<=1; x++){
          sum+=x;
        }
      }
        else{
          for(int x=1; x<=N; x++){
            sum+=x;
          }
        }
    }
    System.out.println(sum);
  }
}

System.out.print("Enter the value of N:");
comment this out, automatic checker doesn't know that this text isn't the part of your answer

yup did that too and it still says wrong answer

Okaaaaay...

if(N<10000){
i assume you wanted to check here if input data is correct, but there's no need to do that, input data is correct by default.
Not to mention that you do it wrong, you check if N is between (-infinity; 9999], while N should be between [-10000; 10000].

Also i think you don't handle the N=0 case correctly, but hopefully you'll figure out why without more hints.