SquareDetector.java

package squaredetector;

/**
 * Created by psy on 02.04.14.
 */
public class SquareDetector {

    private final int dimension;
    private final char[][] field;

    public SquareDetector(int dimension, char[][] field) {
        this.dimension = dimension;
        this.field = field;
    }


    public boolean evaluate() {
        return false;
    }

}

SquareMain.java

package squaredetector;

import java.util.LinkedList;
import java.util.List;
import java.util.Scanner;

/**
 * Created by psy on 02.04.14.
 */
public class SquareMain {

    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        List<String> output = new LinkedList<String>();

        int games = Integer.parseInt(in.nextLine());

        for (int i = 1; i <= games; i++) {
            int dimension = in.nextInt();
            char[][] field = new char[dimension][dimension];

            in.nextLine();
            for (int j = 0; j < dimension; j++) {
                field[j] = in.nextLine().toCharArray();
            }

            SquareDetector detector = new SquareDetector(dimension, field);

            boolean result = detector.evaluate();

            output.add("Case #" + i + ": " + (result ? "YES" : "NO"));
        }

        for (String out : output) {
            System.out.println(out);
        }
    }

}