将类的实例添加到Arraylist

Question

我想将一个类的实例添加到arraylist。这是代码：

ArrayList<Edge> edges = new ArrayList<Edge>(); //A List Containing All the Edges & their startNode,endNode

System.out.println("Enter Number of Nodes: ");
int noOfNodes = scan.nextInt();  //Gets Number of Nodes in Graph

int graphmatrix[][] = new int[noOfNodes][noOfNodes];  //Makes a Matrix According to Graph

for ( int i=0; i < noOfNodes; i++ ) {
    for (int j=0; j < noOfNodes; j++) {
        if ( j > i ) {
            System.out.println("Enter Relation Between " + i + " & " + j + ": ");
            int length = scan.nextInt();
            graphmatrix[i][j] = length;
            graphmatrix[j][i] = length;
            Edge edge = new Edge(i, j, length);
            edges.add(edge);
        }
    }       
}
System.out.println(edges);

这是最后一行的输出：

  

[dijkstra.Edge@49e4cb85，dijkstra.Edge@2133c8f8，dijkstra.Edge@43a25848]

如您所见，

问题似乎在于它没有创建arraylist。 我不明白怎么了。 这也是Edge类的构造函数：

public Edge(int startNode, int endNode, int length) {
    this.startNode = startNode;
    this.endNode = endNode;
    this.length = length;
}