Breadth First Search (BFS)

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

class Node {

    int data;
    boolean visited;
    List<Node> neighbours;

    Node(int data) {
        this.data = data;
        this.neighbours = new ArrayList<>();

    }

    public void addneighbours(Node neighbourNode) {
        this.neighbours.add(neighbourNode);
    }

    public List<Node> getNeighbours() {
        return neighbours;
    }

    public void setNeighbours(List<Node> neighbours) {
        this.neighbours = neighbours;
    }
}

class BreadthFirstSearch {

    private Queue<Node> queue;
    static ArrayList<Node> nodes = new ArrayList<Node>();

    public BreadthFirstSearch() {
        queue = new LinkedList<Node>();
    }


    public void bfs(Node node) {
        //Lengkapi
        queue.add(node);
        node.visited = true;
        while (!queue.isEmpty()){
            Node isi = queue.remove();
            System.out.print(isi.data + " ");
            List<Node> neighbours = isi.getNeighbours();
            int i = 0;
            while (i < neighbours.size()){
                Node check = neighbours.get(i);
                if(check != null && !check.visited){
                    queue.add(check);
                    check.visited = true;
                }
                i++;
            }
        }
    }

    public void bfs(Node[] nodes, int mulai){
        for (int i = 0; i < nodes.length; i++) {
            if (nodes[i].data == mulai) {
                bfs(nodes[i]);
                break;
            }
        }
        System.out.println("");
    }

}

public class BFSMain {

    public static void main(String arg[]) {
        Scanner in = new Scanner(System.in);
        BreadthFirstSearch BFS = new BreadthFirstSearch();
        String input[] = in.nextLine().split(" ");
        Node[] nodes = new Node[input.length];
        for (int i = 0; i < input.length; i++) {
            nodes[i] = new Node(Integer.parseInt(input[i]));
        }
        int n = in.nextInt();
        for (int i = 0; i < n; i++) {
            int A = in.nextInt();
            int B = in.nextInt();
            nodes = addneighbour(nodes, A, B);
        }
        int mulai = in.nextInt();
        BFS.bfs(nodes, mulai);
    }
    public static Node[] addneighbour(Node[] nodes, int A, int B){
        for (int i = 0; i < nodes.length; i++) {
            if (nodes[i].data==A) {
                for (int j = 0; j < nodes.length; j++) {
                    if (nodes[j].data==B) {
                        nodes[i].addneighbours(nodes[j]);
                    }
                }
            }
        }
        return nodes;
    }
}