Use a custom comparator:

Collections.sort(nodeList, new Comparator<DataNode>(){
public int compare(DataNode o1, DataNode o2){
if(o1.degree == o2.degree)
return 0;
return o1.degree < o2.degree ? -1 : 1;
}
});

You can use the Bean Comparator to sort on any property in your custom class.

Modify the DataNode class so that it implements Comparable interface.

public int compareTo(DataNode o)
{
return(degree - o.degree);
}

then just use

Collections.sort(nodeList);