Как прочитать n числовых строк из консоли?

попробуй это:

Scanner reader = new Scanner(System.in);
    List<String> a = new ArrayList<>();
    while (reader.hasNextLine()) {
        String s = reader.nextLine();
        if (s.equals("!q")) {
            break;
        }
        a.add(s);
    }

вы можете попробовать это:

import java.util.*;  
public class ScannerClassExample1 {    
      public static void main(String args[]){                       
          String s = "Hello, This is JavaTpoint.";  
          //Create scanner Object and pass string in it  
          Scanner scan = new Scanner(s);  
          //Check if the scanner has a token  
          System.out.println("Boolean Result: " + scan.hasNext());  
          //Print the string  
          System.out.println("String: " +scan.nextLine());  
          scan.close();           
          System.out.println("--------Enter Your Details-------- ");  
          Scanner in = new Scanner(System.in);  
          System.out.print("Enter your name: ");    
          String name = in.next();   
          System.out.println("Name: " + name);           
          System.out.print("Enter your age: ");  
          int i = in.nextInt();  
          System.out.println("Age: " + i);  
          System.out.print("Enter your salary: ");  
          double d = in.nextDouble();  
          System.out.println("Salary: " + d);         
          in.close();           
          }    
}  

и вывод будет таким:

Boolean Result: true
String: Hello, This is JavaTpoint.
-------Enter Your Details--------- 
Enter your name: Abhishek
Name: Abhishek
Enter your age: 23
Age: 23
Enter your salary: 25000
Salary: 25000.0