//list of car license plates, numbers are always of the same standard type // need to output each number separately to the console // then create a map of number to its digits (example A123BC:123) where key is the license plate and value is the digits //var autoNumbers = List.of(List.of("A123BC", "B421FT"), List.of("O543EC","B421FT", "I2220A"));

To solve the task in Java, you can use the following approach:

1. Iterate through the nested lists and print each number to the console.
2. Create a Map where the key is the car number, and the value is a string of digits from the number.

Example code:

import java.util.*;
import java.util.stream.*;

public class AutoNumbers {
    public static void main(String[] args) {
        var autoNumbers = List.of(
            List.of("A123BC", "B421FT"),
            List.of("O543EC", "B421FT", "I2220A")
        );

        // Print each number to the console
        autoNumbers.stream()
            .flatMap(Collection::stream)
            .forEach(System.out::println);

        // Create a map from number to digits
        Map<String, String> numberToDigits = autoNumbers.stream()
            .flatMap(Collection::stream)
            .distinct() // to avoid duplicate keys
            .collect(Collectors.toMap(
                number -> number,
                number -> number.replaceAll("[^0-9]", "")
            ));

        // Example output of the map
        numberToDigits.forEach((key, value) -> System.out.println(key + ":" + value));
    }
}

In this example:

• flatMap is used to merge nested lists into a single stream.
• The method replaceAll("[^0-9]", "") extracts only the digits from the string.
• distinct() removes duplicate numbers so that the keys in the Map are unique.