I can't understand where is the error

Question

When I use nextInt to read the input as int I recibe the error, but if I change the variable"a" in the last line with 0 the Code run.

import java.util.HashMap;
import java.util.Scanner;

public class datass{
HashMap<Integer,String> points = new HashMap<Integer,String>();
public String search_in(int number){
return points.get(number);
}
public void add_row(int a,String name){
points.put(a,name);
}
}

public class MyClass {
public static void main(String[ ] args) {

datass id_person = new datass();

Scanner pal = new Scanner(System.in);
Scanner num = new Scanner(System.in);

String words = pal.nextLine();
id_person.add_row(0,words);

int a = num.nextInt();

System.out.println(id_person.search_in(a));
}
}

Answer 1

it is not a good idea to use two scanners for System.in (it produces errors), use one for it

Scanner in = new Scanner(System.in);
//Scanner num = new Scanner(System.in);
String words = in.nextLine();
id_person.add_row(0,words);
int a = in.nextInt();

keyboard input:
Pablo
0

Output:
Pablo

Answer 2

Thank you very much!! That was the problem. :)