Primality test Java

import java.io.*;

class file name{
		public static void main(String[]args) throws IOException
		{
			BufferedReader br =
				new BufferedReader(new InputStreamReader(System.in));
			
			System.out.print("Please enter a positive integer");
			String str = br.readLine();
			int a =Integer.parseInt(str);
			
			boolean sosu = true;
			
			if(a == 1)sosu = false;
			
			for(int b = 2; b*b <= a; b++){
				if(a%b == 0){
					sosu = false;
					break;
				}
			}
			
			if(sosu == true) System.out.println("\n"+a+"Is a prime number");
			else System.out.println("\n"+a+"Is not a prime number");
			
			
		}
}

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