Yes, you can used the private member of a class in a public function.But private modifier does not allow to access the private member of a class in another class.

class PrivateModifier {
     private int x=10;
     private int y=5;

  public void getdata()
     {
        System.out.println(x);
        System.out.println(y);

     }
     public static void main(String[]args){
         PrivateModifier p=new PrivateModifier();
         p.getdata();
     }
}