Graph in Java

import java.util.LinkedList;

public class Graph {

LinkedList<Integer>[] adj;
int V;

public Graph(int vertices) {
    V = vertices;
    adj = new LinkedList[V];
    for(int i = 0; i < V; i++) {
        adj[i] = new LinkedList<Integer>();
    }
}

public void addEdge(int from, int to) {
    // Adding an edge between from and to.
    adj[from].addFirst(to);
    // For undirected graphs, do the same in reverse (below)
    // adj[to].addFirst(from);
}

public int size() {
    return V;
}

public LinkedList<Integer> getEdges(int vertex) {
    if(vertex > V) return null;
    return adj[vertex];
}
}