jdbc-protolib/src/main/java/com/streamsets/pipeline/lib/jdbc/multithread/util/CycleDetector.java
boolean isGraphCyclic() {
    for (V vertex : directedGraph.vertices()) {
      boolean areThereCycles = findCycles(new LinkedHashSet<V>(), vertex);
      if (areThereCycles) {
        return true;
      }
    }
    return false;
  }
boolean isGraphCyclic() {
    for (V vertex : directedGraph.vertices()) {
      boolean areThereCycles = findCycles(new LinkedHashSet<V>(), vertex);
      if (areThereCycles) {
        return true;
      }
    }
    return false;
  }
Find cycles in the {@link #directedGraph}.
@return Set of list of vertices involved in the cycle.