Eclipse Java help for students

// Till.java (ours): compiles in neither javac nor Eclipse
import java.util.Scanner;

public class Till {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        int total;
        String item = in.nextLine();
        if (item.equals("pen")) {
            total = 2;
        }
        System.out.println(total);
        Thread.sleep(500);
    }
}

Ours. Three separate problems: a Scanner never closed, a variable that only gets a value on one path, and a method that can throw without saying so.

Eclipse Compiler for Java (ecj 3.46.100), our run:
1. WARNING in Till.java (at line 5)
Resource leak: 'in' is never closed
2. ERROR in Till.java (at line 11)
The local variable total may not have been initialized
3. ERROR in Till.java (at line 12)
Unhandled exception type InterruptedException
3 problems (2 errors, 1 warning)

Our run, ecj 3.46.100 with resource warnings switched on (-warn:+resource), 17 October 2026, trimmed to the message lines. Eclipse shows the same messages in the Problems view.

// Till.java, repaired (ours)
import java.util.Scanner;

public class Till {
    public static void main(String[] args)
            throws InterruptedException {
        try (Scanner in = new Scanner(System.in)) {
            int total = 0;
            String item = in.nextLine();
            if (item.equals("pen")) {
                total = 2;
            }
            System.out.println(total);
            Thread.sleep(500);
        }
    }
}

typed: pen
printed: 2

Ours, compiled with ecj 3.46.100 with no problems reported, then run: typing pen printed 2. Each change answers one message: a starting value, a throws clause, and try with resources to close the Scanner.