Depth-first Search in Java

import java.util.LinkedList;
import java.util.Stack;

public class DFS {

// Primitive definition of a Graph.
public static class Graph {
    LinkedList<Integer>[] adj;
    int size;
}

// Iterative DFS implementation.
public static void dfsIterative(Graph G, int startVert) {
    
    boolean[] visited = new boolean[G.size];
    Stack<Integer> s = new Stack<>();
    
    visited[startVert] = true;
    s.push(startVert);
    
    while (!s.isEmpty()) {
        int vert = s.pop();
        for(int adjV: G.adj[vert]) {
            if (!visited[adjV]) {
                visited[adjV] = true;
                s.push(adjV);
            }
        }
    }
}

// Recursive DFS that allows for function calls before and after visits.
public static void dfsRecursive(Graph G, int startVert) {
    boolean[] visited = new boolean[G.size];
    dfsAux(G, startVert, visited);
}

private static void dfsAux(Graph G, int v, boolean[] visited) {
    visited[v] = true;
    for(int adjV: G.adj[v]) {
        if(!visited[adjV]) {
            dfsAux(G, adjV, visited);
        }
    }
}
}