Simple DFS Traversal using Java

/*
 * To change this license header, choose License Headers in Project Properties.
 * To change this template file, choose Tools | Templates
 * and open the template in the editor.
 */
package main;

/**
 *
 * @author markjasongalang
 */

/**
 *
 *  Use this as input: (copy-paste in terminal)
 *  3
 *  4 2
 *  1 2
 *  2 3
 *  5 3
 *  1 2
 *  2 3
 *  1 3
 *  6 3
 *  1 2
 *  3 4
 *  5 6
 *
 */

import java.io.*;
import java.util.*;

public class Main {
    static LinkedList<Integer> a[];
    static boolean visited[];

    static void DFS(int u) {
        visited[u] = true;
        ListIterator it = a[u].listIterator(0);
        while (it.hasNext()) {
            int v = (int) it.next();
            if (!visited[v]) {
                System.out.print(" -> " + (v + 1));
                DFS(v);
            }
        }
    }

    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        int tt = in.nextInt();
        for (int qq = 1; qq <= tt; qq++) {
            int n = in.nextInt();
            int m = in.nextInt();
            a = new LinkedList[n];
            for (int i = 0; i < n; i++) {
                a[i] = new LinkedList();
            }
            for (int i = 0; i < m; i++) {
                int u = in.nextInt();
                int v = in.nextInt();
                --u; --v;
                a[u].add(v);
                a[v].add(u);
            }
            visited = new boolean[n];
            Arrays.fill(visited, false);
            for (int u = 0; u < n; u++) {
                if (!visited[u]) {
                    System.out.print(u + 1);
                    DFS(u);
                    System.out.println();
                }
            }
            System.out.println("");
        }
    }
}