Cycle Detection in Directed Graph

boolean hasCycle(List[] graph) {
  int[] color = new int[graph.length]; // 0=WHITE, 1=GRAY, 2=BLACK
  for (int i = 0; i < graph.length; i++)
    if (color[i] == 0 && dfs(i, graph, color)) return true;
  return false;
}
boolean dfs(int u, List[] graph, int[] color) {
  color[u] = 1;
  for (int v : graph[u]) {
    if (color[v] == 1) return true;
    if (color[v] == 0 && dfs(v, graph, color)) return true;
  }
  color[u] = 2;
  return false;
}