Kruskal's algorithm in Java - follow-up

Question

The previous and initial iteration at Kruskal's algorithm in Java

Now what I did is remove the fields and let the actual Kruskal-routine create the required data structures in the local scope, which leads to thread safety.

The only file that changed is KruskalMSTFinder.java:

package net.coderodde.graph.mst.support;
import java.util.ArrayList;
import java.util.Collections;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;
import net.coderodde.graph.UndirectedGraphEdge;
import net.coderodde.graph.UndirectedGraphNode;
import net.coderodde.graph.WeightFunction;
import net.coderodde.graph.mst.MSTFinder;
public class KruskalMSTFinder implements MSTFinder {
 @Override
 public List<UndirectedGraphEdge> 
 findMinimumSpanningTree(final List<UndirectedGraphNode> graph,
 final WeightFunction weightFunction) {
 final Map<UndirectedGraphNode, 
 DisjointSet<UndirectedGraphNode>> map = new HashMap<>();
 final Set<UndirectedGraphEdge> edgeSet = new HashSet<>();
 final List<UndirectedGraphEdge> edgeList = new ArrayList<>();
 prepareEdgeList(graph, 
 weightFunction,
 map,
 edgeSet,
 edgeList);
 final List<UndirectedGraphEdge> minimumSpanningTree = new ArrayList<>();
 for (final UndirectedGraphEdge edge : edgeList) {
 final UndirectedGraphNode u = edge.firstNode();
 final UndirectedGraphNode v = edge.secondNode();
 DisjointSet<UndirectedGraphNode> us = map.get(u);
 DisjointSet<UndirectedGraphNode> vs = map.get(v);
 us = us.find(us);
 vs = vs.find(vs);
 if (us != vs) {
 minimumSpanningTree.add(edge);
 us.union(vs);
 }
 }
 return minimumSpanningTree;
 }
 private void 
 prepareEdgeList(final List<UndirectedGraphNode> graph,
 final WeightFunction weightFunction,
 final Map<UndirectedGraphNode,
 DisjointSet<UndirectedGraphNode>> map,
 final Set<UndirectedGraphEdge> edgeSet,
 final List<UndirectedGraphEdge> edgeList) {
 for (final UndirectedGraphNode node : graph) {
 map.put(node, new DisjointSet<>());
 for (final UndirectedGraphNode neighbor : node) {
 edgeSet.add(
 new UndirectedGraphEdge(node, 
 neighbor, 
 weightFunction
 .get(node, neighbor)));
 }
 }
 edgeList.addAll(edgeSet);
 Collections.<UndirectedGraphEdge>sort(edgeList);
 }
}

Anything else to improve?