Parse a key=value Config

/*
 * Problem : Process lines.
 * Input   : Several lines.
 * Output  : One answer per query.
 * Approach: Split at the first =.
 * Time    : O(n)
 * Space   : O(n)
 * Java    : 8 or newer.
 */
import java.util.Scanner;

public class Main {
    // This method solves the task. It receives the input and returns the answer.
    static String[] solve(String[] lines) {
        // Step 1: Read the config lines until the line "---". Split each line at the FIRST "=" only.
        java.util.Map<String, String> config = new java.util.HashMap<>();
        int index = 0;
        while (!lines[index].equals("---")) {
            int equals = lines[index].indexOf('=');
            String key = lines[index].substring(0, equals).trim();
            String value = lines[index].substring(equals + 1).trim();

            // Step 2: put replaces an old value, so the last value wins.
            config.put(key, value);
            index++;
        }

        // Step 3: The rest of the lines are queries. Answer each one.
        String[] output = new String[lines.length - index - 1];
        for (int i = index + 1; i < lines.length; i++) {
            output[i - index - 1] = config.getOrDefault(lines[i], "missing");
        }
        return output;
    }

    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        java.util.List<String> all = new java.util.ArrayList<>();
        while (scanner.hasNextLine()) {
            String line = scanner.nextLine().trim();
            if (!line.isEmpty()) {
                all.add(line);
            }
        }
        String[] lines = all.toArray(new String[0]);
        System.out.println(String.join("\n", solve(lines)));
    }
}