Depth First Search (DFS)

import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;
import java.util.Stack;

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 DepthFirstSearch {

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

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

}

public class DFSMain {

    public static void main(String arg[]) {
        Scanner in = new Scanner(System.in);
        DepthFirstSearch DFS = new DepthFirstSearch();
        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();
        DFS.dfs(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;
    }
}