I need help in java use anythitg except Method bollean 2 W

 I need help in java  use anythitg except (Method , bollean )  2. Write a JAVA program to read a number from user  and then find out all prime numbers up to that number.  For Example, if user enters 10, then your program should show: The prime number up to 10 are: 2, 3, 5, 7  if user enters 0, then your program should show: The prime number up to 10 are: 2, 3, 5, 7, 11, 13, 17, 19  

Solution

PrimeNumbers.java

import java.util.Scanner;
class PrimeNumbers
{
   public static void main (String[] args)
   {
      Scanner scanner = new Scanner(System.in);
      int i =0;
      int num =0;
      //Empty String
      String primeNumbers = \"\";
      System.out.println(\"Enter a number to find out all prime numbers up to that number : \");
      int n = scanner.nextInt();
      if(n==0 || n==1)
      {
         n=20;
         for (i = 1; i <= n; i++)
      {
         int counter=0;
         for(num =i; num>=1; num--)
         {
        if(i%num==0)
        {
       counter = counter + 1;
        }
   }
   if (counter ==2)
   {
        //Appended the Prime number to the String
        primeNumbers = primeNumbers + i + \" \";
   }
      }
      }
      else{
      for (i = 1; i <= n; i++)
      {
         int counter=0;
         for(num =i; num>=1; num--)
         {
        if(i%num==0)
        {
       counter = counter + 1;
        }
   }
   if (counter ==2)
   {
        //Appended the Prime number to the String
        primeNumbers = primeNumbers + i + \" \";
   }
      }
      }
      System.out.println(\"The prime number up to \"+n+\" are :\");
      System.out.println(primeNumbers);
   }
}

Output :

Enter a number to find out all prime numbers up to that number :
10
The prime number up to 10 are :
2 3 5 7

Enter a number to find out all prime numbers up to that number :
0
The prime number up to 20 are :
2 3 5 7 11 13 17 19